Evernote:
Where most mobile companion apps tend to offer a lot less than their desktop counterparts, ubiquitous capture tool Evernote takes full advantage of the iPhone to make the mobile app worthy of standing on its own. In addition to capturing regular text, you can grab voice notes and photos as well. Since Evernote performs OCR (optical character recognition) on all your images, any text in the pictures you add to Evernote will be searchable. For example, you could take a snapshot of a menu in a restaurant and later search it just like it was a text document.
[Download]

Simplenote:
Simplenote is a key component in the holy grail of ubiquitous text capture, and rightfully so. Simplenote allows for speedy note entry on your iPhone, plus it syncs with the likewise free Simplenote service so your notes are always available wherever you want them.
[Download]

TripIt:
If you haven't used TripIt to manage your travel itineraries, you've been missing out. We've already discussed its merits, but the free iPhone app makes it even easier to manage your trip. It's a natural extensions of the service, since if you're traveling it's more than likely that you're not at your computer.
[Download]

Instapaper / ReadItLater:
Instapaper and ReadItLater both serve the purpose of saving web content for later reading, and both offer free and paid versions, but they're still notably different. Instapaper offers you a straightforward and simple way of reading saved content. ReadItLater is a little more feature-rich. Both are great options and you can try them for free to see which you prefer.
[Download Instapaper Free / Instapaper (Paid) or ReadItLater Free / ReadItLater Pro]

Dragon Dictation:
Apple's voice recognition handles a few tasks but misses some key features that Dragon Dictation helps to fill in. If typing is not an option, or you're just feeling lazy, Dragon Dictation will type it up for you. You can send a text message or an email directly from the app, and it also integrates with Facebook and Twitter. Although not perfect, Dragon Dictation is surprisingly accurate and will let you correct any mistakes it makes.
[Download]

Mint: If you're not using Mint to keep track of you finances, you should be. It'll keep track of all your accounts and provide you with useful statistics and budgeting information to help you manage your money better. If you're looking for something a little more hands-on, however, Jumsoft Money is a great free app as well—you just input everything yourself.
[Download]

Atomic Browser:
If you've found Mobile Safari to be a bit lacking, you're not alone. Atomic Browser can help, providing true tabbed browsing, private browsing mode, user-agent spoofing (handy for watching Netflix on your iPhone), and a ton of features you've come to expect as part of your web-browsing experience.
[Download Full Version or Lite]

Skype:
Imagine being able to use your iPhone to make phone calls! (Har har.) Now that Skype works over 3G and can take advantage of iOS 4's multitasking capabilities, it's actually a viable alternative to using your mobile minutes. Even if you don't want to go so far as to replace your regular phone, it's still a great tool for making international calls on the cheap and chatting with your Skype contacts on the go.
[Download]

Textfree Unlimited:
If you don't like paying a ridiculous amount of money for small amounts of data, Textfree Unlimited lets you send and receive text messages at no costs. You can even set up a phone number specifically for the app. While Textfree used to only provide free text messages, now the app is free as well. The trade-off is that you get ads, but you have the option to pay to remove them.
[Download]

LucyPhone:
Another great minute-saver is LucyPhone (check out our quick review), the app that waits on hold so you don't have to. If you're calling a popular business, LucyPhone's directory may even save you the step of going through the phone tree to get to the right department. While you might confuse the customer service representative on the other end, LucyPhone takes all the pain of waiting on hold—including the loss of your mobile minutes.
[Download]

Meebo:
With a couple of $10 multi-service IM clients available, Meebo stands out especially because it's free. Being free doesn't make it bad, however. It's an attractive app with the ability to integrate tons of IM services, making it our IM app of choice.
[Download]

Twitter:
You could drown in Twitter apps on the iPhone, but the official option is free and one of the best. In addition to tweeting and direct-messaging, you can also share photos and videos. Thanks to the iPhone's GPS, Twitter is location-aware and can provide you with nearby tweets so you can figure out what people are talking about in your area in real time.
[Download]

Facebook:
The official Facebook app on the iPhone is great for general updates and messages, but it becomes especially useful when all your contacts flood in. If your address book is missing a number, just find your friend in the Facebook app and click the call button. You can also keep track of events, check your news feed, and edit your profile.
[Download]

Maps (Default App):
While Android's version of Google Maps blows it out of the water, the built-in Maps application on the iPhone is still pretty great. Drivers can check real-time traffic and get simple directions to just about anywhere. Even if you don't drive, walking and public transportation directions are available. With street view integration and a few other neat features, Maps is easily one of the most useful apps on the iPhone.

MapQuest4Mobile (GPS):
While the iPhone has a few free turn-by-turn navigation apps (and none of them are even encroaching on the territory of perfect), MapQuest4Mobile feels more like the real deal than any of the others. In my personal experience I found it gave directions too late in quite a few cases, it's hard to argue with free. If you want a commanding, computerized female voice barking directions at you (occasionally after you've missed your exit), and you don't want to pay a lot for the privilege, you've found your match.
[Download]

GasBuddy:
Although not free (weighing in on the more expensive side at $2.99), GasBuddy is the sort of app that can pay for itself after one use. If you're always on the lookout for cheap gas, GasBuddy will give you options by proximity and price. You can filter by fuel grade, and it can even help you find a diesel gas station.
[Download]

Movies Now:
If you've ever wanted to see a movie on a whim, Movies Now scratches that itch. While it handles regular movie showtimes, too, it's main function uses your location and the current time to find upcoming showtimes near you. If you find a movie you like, you can buy tickets through movietickets.com directly from the app. The catch: It's $2. While there are certainly free options in the movie showtimes arena (like the IMDb app below), Movies Now has a great location-based twist.
[Download]

RunKeeper Free:
You have quite a few fitness apps to choose from on the iPhone. One of those happens to be RunKeeper, and lucky us, it has a great free version. RunKeeper uses your iPhone's GPS to track your run and provide you with statistics, giving you the statistical benefits of a treadmill when you're outside the gym. It integrates with your music library and lets you share your activities. While the built-in Nike+ app is also pretty nice, RunKeeper doesn't require the purchase of any additional hardware and lets you choose your brand of shoes.
[Download Free or Pro]

Find My iPhone:
Even if you're not a MobileMe subscriber, you've probably heard a bit about Find My iPhone in the news. It's already tracked down a few iPhone thieves, but is probably more commonly used when you've just misplaced your phone. While you have to shell out $99 a year for a MobileMe account to get any use out of the app, it's a must if you're already a MobileMe subscriber.
[Download]

Dropbox:
Would it truly be a Lifehacker Pack without file-syncing app extraordinaire Dropbox? While the iPhone version of Dropbox isn't quite as useful as Dropbox on your computer, it makes for a nice companion. If you're using Dropbox for all sorts of clever things, it's always nice having access to your sync'd files from your phone. While the Dropbox app can download anything the iPhone (or a third-party app) can display, you can also save key files on your phone as well.
[Download]

Boxcar:
If you like frequent push notifications, you'll probably like Boxcar. Boxcar integrates with Twitter, Facebook, email, RSS, and Growl to grab updates of nearly anything you want and push them to your phone. If you want to be alerted the moment something changes, Boxcar will get the job done.
[Download]

PasteFire / MyPhoneDesktop:
PasteFire and MyPhoneDesktop do the same thing—they aim to make getting text from your desktop to your iPhone a bit easier. Both use push and both integrate with your machine to send content. The biggest difference is price: PasteFire is free and MyPhoneDesktop costs a whopping $5. So why mention MyPhoneDesktop? I think it works better. Still, no penalty for trying PasteFire. MyPhoneDesktop is really only worth a look if the free option doesn't cut it for you.
[Download PasteFire or MyPhoneDesktop]

Logitech TouchMouse:
If you want to use your iPhone as a wireless trackpad for your Mac or Windows PC, that's precisely what Touch Mouse can help you accomplish. It also includes keyboard functionality so you can make use of your iPhone's keyboard to input text. While this is not terribly practical or speedy for use with just any machine, if you have a computer hooked up to your television it's a convenient way to navigate without the clutter of a keyboard and mouse on your couch.
[Download]

Pandora:
Pandora's always been a favorite on the iPhone, but with multitasking support in iOS 4 it becomes so much more useful. Now that you can listen to your personalized Pandora radio stations in the background, you'll be hard-pressed to find a better, free way to discover new music.
[Download]

Remote:
Although it's nearing a year without an update, Apple's Remote app is still pretty incredible. If you want to control your iTunes library remotely, or turn your iPhone into a multi-room wireless remote (in the event your have an Airport Express or AppleTV), there's really no better option—especially for free.
[Download]

Air Video / StreamToMe:
Air Video and StreamToMe are both apps that help you stream video from your computer to your iPhone, no matter where you are. They're especially compelling when you want to watch something at, say, the gym and you didn't have time to transcode and sync it to your device first. Whether you're connected to Wi-Fi or 3G, you can stream video directly to your phone from anywhere you are (the quality of your connection permitting, of course). Both apps have some subtle differences, such as StreamToMe's ability to stream more than just video and Air Video's option to pre-encode content for easier streaming, and either are worth the price of admission: $2.99.
[Download Air Video or StreamToMe]

iBooks / Kindle / Stanza:
It's hard to consider any of the iPhone ebook readers the best choice because they're pretty similar. They all let you read on your phone, they all let you purchase books, and they're all free to download. While I'm partial to the Kindle app, it's mainly because I started with ebooks via the Kindle. Pick the ebook app that works the best for you—or don't, since they're all free downloads.
[Download iBooks, Kindle, or Stanza]

Yelp:
Yelp has yet to fail me when I'm on a search for some good, nearby eats. It also comes with some semi-secret, fully-nifty augmented reality. If you're looking for nearby food (or anything, really), Yelp is a great (free) way to find your best options.
[Download]

MenuPages:
The one things Yelp won't do is hand you a menu for the restaurants it suggests, and that's where MenuPages comes in. While it can feel a little clunky at times, it's indispensable when you're in the need of a menu on the go.
[Download]

IMDb:
IMDb is a great resources for movie information, and the app does a good job of focusing a lot of information onto your iPhone's small screen. What's also great about the IMDb app is that it also serves as an excellent free option for finding movie showtimes.
[Download]

TV Forecast:
TV Forecast performs the simple function of keeping track of when the next episode of any show is going to air. Enter in just about any show that's currently running and TV Forecast will provide you with an attractive schedule tailored just for you. While you can grab the free version of TV Listings instead and save yourself $1.99, TV Forecast is a better option.
[Download]

PhoneFlicks:
While you can always watch Netflix on your jailbroken iPhone with a little work, if you're looking for a way to manage your old-fashioned Netflix queue you can do that nicely with PhoneFlicks. The functionality here is pretty basic, letting you edit your queue and find new titles through search or browsing, but it gets the job done and doesn't cost you a penny.
[Download]

GorillaCam:
If you're looking for a free, full-featured iPhone camera upgrade you should check out Joby's GorillaCam. It provides a huge set of features, including a self-timer, time-lapse photography, anti-shake, three-shot burst, and more. Update: We're hearing that Gorillacam may have a potential spyware issue. While we can't tell for certain, you may want to proceed with caution.
[Download]

Snapture:
If you really want to make the most of your iPhone's camera, check out Snapture. It might set you back $1.99, but it's a popular alternative to the iPhone's built-in camera app. In addition to helping you take better photos, you'll also find some basic image editing tools. Snapture's main draw, however, is how easy it makes it to quickly pull out your iPhone and take a picture. Simply open the app, tap the screen, and you've got a photo.
[Download]

HipstaMatic:
HipstaMatic aims to emulate old cameras and film stocks, providing some pretty compelling results. But be warned: it's one of those apps that can get pretty addictive, and you can shell out $1 each time you want to try out a new lens or flash.
[Download]

Pano:
Pano's not particularly cheap, at $3, but it can create some enormous, impressive panoramas right on your iPhone. It works by taking multiple shots and stitching them together. While the results aren't always perfect, they're often stunning.
[Download]

SketchBook:
While SketchBook is the sort of app that excels on a big screen, like the iPad's, it's nonetheless a great drawing app on the iPhone. With several brushes and pencils, you'll be surprised what you can actually draw with this app. When you're done, you can even export a PSD (Photoshop Document) or the flattened image. $3, but if you're really into sketching, you'll likely consider it worth the price..
[Download]