Kensington Vo200 Bluetooth internet phone
The Kensington Vo200 is a credit card sized Bluetooth internet phone, that can be recharged in any standard PCcard slot. Cost is less than 80 Euros. Officially only compatible with Windows, but I managed to recharge it in a PowerBook G4 PCcard slot and pair it under MacOSX 10.4.10 without any troubles. Shows up as a standard audio input and output device.