iPhone as a touchpad
Telekinesis is still awesome, but this app basically turns your iPhone into a remote for your whole computer. Anything you can do by moving and clicking a mouse around, you can do with this. Very neat. It is too bad that it requires Installer.app, and that it has to be done unofficially, but the official SDK is still (hopefully) just around the corner. I remain amazed at how much programmers like Jahanzeb and the vnsea guys (and anyone else working on the iPhone) are able to do unofficially.