I had previously written about getting a bluetooth headset to work with Skype on my powerbook, when I was using OS X 10.3. I stopped using it for a while, and when I tried to use it today (having long since upgraded to 10.4) it didn't work. Tiger has newer bluetooth software which is headset ready, however even after removing the bluetooth device and re-pairing it, it was still not showing up as a device in the sound preferences (or in Skype or iChat). The following is the process I used to get it working again:

1. Delete the headset device in bluetooth preferences.
2. chmod /var/root/Library/Preferences/blued.plist so that you have write permissions
3. Make a backup of blued.plist
4. Using property list editor, open blued.plist
5. Delete the headset device listed under DeviceCache
6. Save
7. Reboot
8. Use the bluetooth preferences to set up a new device.