I was surprised to find that even though many of the Pocket PC phones have Bluetooth headphone support, you can not direct Media Player to output through the Butooth headset. I was told that was true for the 6700 from Sprint & the MDA from T-Mobile. At least that's what T-Mobile tech support told me when I got my new MDA home and tried to set it up. I got the same answer from the Sprint tech when I asked at the store.
If anyone knows this not to be true or has a workaround please let me know. I loved the MDA phone for the 3 days I had it but could not accept this limitation. I walk to work and like to listen to Podcasts and such as I walk along.
The audio gateway BT profile isn't that common on phones yet, I'm afraid. Some HP models support it but that's about it. If there are hacks for the BT stack to add profiles on those two models, you'd likely find them on www.xda-developers..com .
-------------------- Lisa Gade Editor in Chief, MobileTechReview