This is only pseudo mac compatible I've found. If you're running any updates past 10.3.2 they don't support them and for me it constantly locks up my 12" iBook G4.
Are you absolutley stuck on USB versions. ethernet versions are OS independent and require no drivers. they are a bit more expensive, but from what I've seen from other people's comments, the ethernet ones are much more reliable. I ahve a linksys WET11 and its been great.