I recently bought a USB wireless optical mouse at Aldi's in hopes of using it with my iBook. I bought it despite not mentioning OS X support on the packaging, due to my confidence in OS X working with it anyway. When it did indeed fail to work out of the box, I downloaded USB Overdrive.
This nifty program did indeed recognize the mouse and made it functional, except for the fact that after the iBook wakes from sleep, the mouse isn't recognized unless I "retrain" the dongle and mouse by pushing the little buttons on each. Not a big deal, except the button on the mouse is recessed, requiring something pointy to push it in. Too much trouble.
I can't really blame the mouse, as they don't specify OS X compatibility, but unless I can use the mouse without retraining it each time the iBook wakes up, I really can't justify supporting USB Overdrive with my $$$. Oh, well.