There have been a number of Bluetooth devices that can pipe music from an MP3 player and then switch over to pick up a phone call, but few are as elegant as this little disk. The Blueye connects between your MP3 player and your headphones and acts as a microphone, plus it can switch between incoming and outgoing calls and a constant stream of music. You can also take a call just by speaking into the microphone. Should be about $121 and lasts 10 hours on one charge.
Blueye music and mobile integration [TechDigest]