I bought an iMac G4 a while back (in my signature). It has a Wifi/Bluetooth card in it. The Wifi was pretty spotty if I wasn't in the same room as the router. I recently found an older Microsoft Bluetooth mouse at my mom's. I paired it with my MBP and it works great. When I tried pairing it with the iMac (which is where I really wanted to use it) I cannot get them to find each other. This is the only Bluetooth device I have, other than my iPhone. I tried pairing iPhone and iMac and they couldn't find each other either. Could this be an issue where the devices just aren't compatible or could there be something wrong with the Wifi/Bluetooth card? System Profiler shows both are installed so I'm not missing anything.