There are way too many Apps on the App Store to go through. It is also harder to find applications that integrate to desktop applications. Here are 6 iPhone Apps that add some value to their Mac Desktop App counterparts.

Evernote - a note capturing application that uses a cloud. Your notes everywhere. The desktop application allows you to easily take both full and partial screenshots, text notes, and even some OCR. On the iPhone app, you can take a photo note using the iPhone camera or manually type out some text notes. Everything syncs up to the cloud and is available to you online at any internet accessible computer, your phones or desktop app.

Things - Things is a task management program from CulturedCode. Providing a beautiful and easy to use interface, Things has elements of David Allen's Getting Things Done, but does not force you to use the system. The Desktop Application has a quick entry form that is easy and simple to fill out. You can have recurring/scheduled tasks, tags, and even sync with your iCal to-dos. The Things iPhone app has a similar interface to the Desktop App, making it easy to use both. Providing sync capabilities with the Desktop App allows you to add/complete/delete your tasks on either platform and have everything sync up. The iPhone App currently does not allow you to add recurring/scheduled tasks, but the folks over at CulturedCode have been working hard at it.

Omnifocus - Omnifocus is another task management application. This one comes from the Omni Group. Omnifocus is a complete Getting Things Done system. This is not just a to do list of any sort. The Desktop Application very flexible and fast. Omnifocus does expect you to use the GTD system. It is a bit harder to get started if you're not familiar with GTD. Omnifocus is a great application for those using GTD. I've found it to be a little bit too involved and require a bit too many steps. The iPhone App for Omnifocus adds Sync supports for tasks, task creation/editing, and organization. One feature that Omnifocus has that Things does not, is Location-Aware. The Omnifocus iPhone App will use the GPS of the iPhone and tell you which tasks you have to complete in the nearby area.

1Password - 1Password is a Password Manager from Agile Web Solutions. 1Password does much more than just Password Management. The Desktop App has integration with Safari, Firefox, Flock, Camino, OmniWeb, DEVONagent, Fluid, and NetNewsWire. It can auto-fill usernames/passwords, Credit Card info and Demographic Info such as addresses. 1Password can also significantly shrink your wallet with their Wallet group where you can save information like credit cards, bank accounts, memberships and reward programs, etc. And of course, this all syncs with the free iPhone App. Although, I haven't tried this myself, 1Password on the iPhone also has the ability to auto-login from the app if you tap a saved login.

Keynote Remote - Keynote Remote is a remote control app for Apple's Keynote 09. It does require you to have Keynote 09. Does not work with Keynote 08. The App costs $0.99 on the App Store. The Keynote Remote lets you use your iPhone or iPod touch to control your presentation from anywhere in the room using Wi-Fi. See your slide with notes or both the current slide and the next slide in the palm of your hand. Just swipe to advance.

Apple iTunes Remote - The iTunes Remote App from Apple allows you to control your iTunes/AppleTV/AirTunes library from your iPhone. You can edit playlists, search, and of course play, pause and volume control. It does require iTunes 8.0 and iTunes to be actively running. Also does work with the Windows version of iTunes 8.