[Edit: Wow, I'm not too good with the search funtion
Already a thread here. A little help Coz?]
I've waited for something like this for a long time. The ability to use your smartphone as a keyboard/mouse with any Bluetooth enabled device. No need for any software running on the host, as this program lets other devices see your PPC as a standard BT HID device. So in theory, this should work with almost any device that supports the HID profile (PC's, PS3's, etc.).
The program includes (among other things) a mouse/trackpad screen, full size on-screen-keyboard, and a media remote for WMP, Media Center, etc.
MobileRemote was developed by
MobileSRC (the same people that made GScroll), and you can pick it up for a reasonable $8.99. Gonna have to give this a try.