I have a Mr Mysza, that I ordered through either
Mr Hardware Computers, or
Software Hut, I forget which. (They both carry it, I think.)
It works well with a Microsoft wheelmouse I have. It doesn't work so well with my Logitech wheelmouse, though. :-( (Actually, I think it's the Logitech's fault, though. It defaults to a really crappy resolution without it's proper driver on a Windows PC, too...)
Anyhow, I'd recommend the piece of hardware, and either place to anyone in North America. (I have no idea of overseas availablility) :-)