A few months ago, I saw the UPS man up at the courthouse wearing this thing. Even though those guys run a hundred miles an hour, he couldn't stop talking about it. It's a stereo bluetooth enabled headset. The UPS guy had a phone that served as an MP3 player which, of course, beamed the music to the headset.
I bought a pair since my phone does the same thing. Greatness. And it has some controls on the side which allows you to answer phone calls. I'll wear it in the car and around the house, but I'm not wearing it out in public.