VetaChat is a client that enables bluetooth chat on Mac OS X.

Veta Chat is an application for communicating with other Mac and soon Palm users via Bluetooth. It is super useful when you need to quickly exchange messages with somebody without drawing the attention of other people - like during those boring meetings that you have to attend. Or you can create a small chat room of up to 7 people on the fly by simply hosting the chat and letting the others join you.