Using ATiny102 as HID device(emulating mouse)
I have build a HID midi keyboard with the hiduino lib which is base on LUFA.
http://code.google.com/p/hiduino/w/list

I know LUFA is also capable to build a HID mouse device. But you need to switch to a bigger controller (i think). I used a 8u2 from atmel.

I used AVR Studio 6 to compile hiduino.
Currently i have no link to the LUFA because the git page is gone. Maybe you find a mirror or a other webpage.