I thought that too, but would still like to know if and how it can be done.
The sales guy at the Sprint/Nextel store sold me a Motorola H700 BT headset($120)

, but after trying it out, it wouldn't work very well if the phone was more than 1 foot away. It had terrible static and after about 3 feet away would cutout completely.

So I did some research and it seems the best BT headset is the Treo($55). I ordered that yesterday and should have it in a few days.
Next I have to get a case and I've done a ton of research, but it didn't help, so I'm going to the flea market this weekend and try different cases and see what works best for me.