I'm a big fan of the Linux compiz cube, but I do most of my work on Windows, so I did a Google search and found Yod'm 3d. It runs pretty good on XP but the initial reaction time is a little slow. I haven't tried it on Vista.
It's been around for a few months but I just ran into it now and no, I'm not the developer. Anyway, I hope someone finds it useful. Also if anyone knows of a better implementation, I'd be interested in trying it out.
