A new app for the iPod touch and iPhone called the Touch Mouse app magically transforms your iPhone or iPod touch into a wireless trackpad and keyboard which can be used in conjunction with your computer. It will perform pretty much like a typical mouse, allowing you to point, click, scroll and type from a distance.
Interestingly it can be used in any application no matter the platform, Mac or PC. The Touch Mouse app also works over Wi-Fi, so you can use it anywhere in the house. Now that is a handy app.