While still not excusing Apple in any way, shape or form from the lamentable absence of A2DP stereo Bluetooth from the iPhone, there's at least a hack of sorts to play music and the audio track from a video through your wireless headset.  Don't get your hopes up too much, though; it's a partial solution at best.

Credit for the tweak goes to Earle Davies, a reader from TUAW, who fathomed the following sequence:

• Pair a Bluetooth headset with your iPhone, switch on your headset so that it can perform the handshake with the iPhone.
• Go into the Visual Voicemail screen and tap the Audio button in the upper right (which is otherwise a Speaker button when your headset isn't on and communicating with your phone)
• You'll receive an audio selection dialog much like the in-call dialog box that allows you to choose where to send the iPhone's audio.
• Select the Headset option, then switch over to the iPod and begin playing music or a video.

The drawback is that audio continues to play through the iPhone's speaker, frustrating if you were hoping to wirelessly enjoy some music on the bus, but less so I suppose if you've fashioned a Bluetooth adaptor attached to your car stereo.

[via iPhoneHacks]