I happen to love my Microsoft Trackball Explorer for playing games, although I've not really played anything demanding since WoW and moving to Snow Leopard. This device was discontinued several years ago and support for it appears to have ceased as of about 2003. As many of you know, the advantage of manufacturer driver software is that it allows you to program button responses that otherwise might be difficult or impossible. Things like have a button be held down as long as you hold your mouse button down or a macro with two different inputs with one button press and more importantly custom settings for individual applications, like a game. The Trackball Explorer uses Intellipoint software and what I used to have showed my specific device and let me do the fancy button programing. A couple days ago I noticed that in my preferences window under "other", I have a Microsoft Mouse icon which denotes the Intelipoint software, but when I click on it, a message pops up telling me to reopen and when I do it says "Microsoft Mouse 32 bit" and there are choices for left button, right button, and scroll. Except my TBE has 4 buttons. I assume the issue popped up when I upgraded to either Snow Leopard or when I got my new MBP and used Time Machine to transfer over all of my settings, but I did not notice. In any case the most recently version of the Intellipoint software at Microsoft was v5. However at Mac.Softpedia.com, I found Intellipoint v8.0.1 which not only shows my Trackball Explorer, appears to have restored my ability to program buttons and add applications, and I'm no longer getting the "Microsoft 32bit" message. FYI!