If you have a T39m, R520m, T68 or T68i cell phone and a Macintosh with Bluetooth, you can now use some software to make your phone act as a remote control for your Mac. You can control Powerpoint, Keynote, iTunes, or any other software that can respond to applescript events. It also has a proximity sensor so that things can happen automatically when you walk away from your computer (like pause iTunes or turn on a security webcam).
Courtesy of MacSlash.