DroidPad: Use your phone as a PC joystick! digitalsquid.co.uk/droidpad
For the time being, visit https://launchpad.net/droidpad-pc to download the computer software.
DroidPad lets you use your phone as a PC joystick or mouse.
Once set up, simply connect your phone via Wifi / USB, press Start, and play any PC game, control your mouse or play a slideshow!
Available for Windows XP, Vista, 7 and Ubuntu Linux; you will need the PC application from http://digitalsquid.co.uk/droidpad/