Mac Wireless Mouse, not apple brand
You can connect any Bluetooth mouse to your MB's integrated bluetooth module. Personally I'd recommend Microsoft mice as they are of good quality. My father recently had some problems with a el cheapo china model, but if you pick a brand, you should not have a problem.

Make sure it has this logo on it, and not some "Yeah we do our own kewl 2.5 GHz radio" (actually there is no reason to do this, except not to pay a few cents for the Bluetooth license):