Bluetooth Headsets - phone and audio player?

I have a Bluetooth headset for my phone. It’s very cool. I look like Locutious of Borg. And I can talk, hands-free, on my cell phone. If it rings I merely reach to my ear, press the little button, and say, “Hello?”

I also have an MP3 player. Wouldn’t it be cool if I had a device like that for my MP3 player?

And then I thought – wouldit it be the coolest if I had ONE device that could do both things? Play music - or, more accurately, wirelessly connect to a device that’s playing music – AND let me talk on the phone.

Does such a thing exist?

If you had a PDA phone or a Treo, you could, but I haven’t ever seen any stereo bluetooth headsets…only mono.