cabgold ...

The A2DP profile is introduced in AKU 2.0 of Windows Mobile v5
But you might get it to work with WM 2003SE on the MPx220.

I'm not gonna try this, but if you are feeling adventurous, then you can checkout:
http://msmobiles.com/news.php/4679.html
AND
http://forum.xda-developers.com/viewtopic.php?t=33532

Of course, one has to have a bluetooth headset capable of stereo, like the Motorola's HT820 and DC800. Or a USB Bluetooth dongle. Just don't forget to select the stream audio to headset setting after pairing. And you might have some issues wit controlling volume ...