I use an older TiBook, without built-in bluetooth. So, when I got an iPaq 6340 and wanted to communicate with it over bluetooth, I went looking for an USB bluetooth adapter, which would work with MacOS X. Apple sells one from D-Link in their online store, but it was back-ordered. I found a cheap adapter from Trust, and decided to try it out. It is a "Trust BT180 Class 1 USB bluetooth adapter", and it works just fine on my powerbook, with MacOS X 10.3.7, without installing any additional drivers.
Recommended.