Service Provider (T-Mobile, Cingular, Sprint, etc): Sprint
Phone brand and model: Samsung M500
works on 770 or 800 or both: Only N800 confirmed
Phone plan (whether it be Voice, Data, Internet....please be specific): SERO Fair & Flexible - Voice, Data, Text

This phone seems to forget some bluetooth devices that it has paired with for some reason, but it remembers my N800 nicely. The phone has rather poor battery life, and only has Bluetooth 1.1, which means that any device is limited to 32KB/s up or down.