I order a wireless mouse from apple. It works great with my powerbook, but my G5 seems to have a range problem. It's very chuncky moving. The G5 is on my desk,so it not realy far way. If I move the mouse closer to it, it works fine.
this is a most common problem.
IMO MacOS X should detect, the first time airport or bluetooth is activated on a current G5 (that needs an antenna, hopefully the next model wont) it warns you about needing the appropriate antenna and has a link to get help with it.
This warning should also be in the Airport/Bluetooth Setup Wizard