(topic split from "SCCAN meeting in May")
This bit of news is actually from the last meeting, but it will get more exposure here.
The mouse adapter that supports many (most?) of the USB mice out there is the TOM2 mouse adapter for the Amiga/Commodore 64 & 128/Atari 8bit and 16bit.
Here's the link on Ebay (there are others) from Poland, where I bought mine...
http://www.ebay.com/itm/Great-Amiga-Atari-XE-XL-ST-C64-C128-Mouse-Gamepad-Joystick-USB-adapter-TOM-Rev2-/231881879211?hash=item35fd3caeab:g:rXAAAOSwr7ZW6~aI (http://www.ebay.com/itm/Great-Amiga-Atari-XE-XL-ST-C64-C128-Mouse-Gamepad-Joystick-USB-adapter-TOM-Rev2-/231881879211?hash=item35fd3caeab:g:rXAAAOSwr7ZW6~aI)
It has other features, to support controllers and a keyboard (for game control).