Rowmote: control your Mac or AppleTV from your iPhone
There are a few different iPhone-based options to remotely control your Mac, but Rowmote might be the most complete. Instead of just controlling your media via Front Row, it can actually switch applications on your Mac. The list of apps you can use from Rowmote is impressive, including everything from PowerPoint to VLC to PandoraJam, and it also works with AppleTV. For 99 cents, that's not too shabby. Rowmote also has some features that greatly improve the user experience. You can set it to keep your Mac's display from sleeping, which is handy when you're watching a movie, and you can also choose between light and dark interfaces, so you don't hurt your eyes if you're using it in the dark. All in all, it might be the best iPhone-to-Mac remote solution I've run across.
