Got it with my Sony Walkman phone about a year ago. It's meant to be connected to the sony ericsson headphones but works with any, it also has that built in radio antenna. About 1m long.
Worked when I used it on my Sony phone a couple of months ago so the radio should be working but not so sure, and it still definatly works as an adapter. £1 including first class postage and paypal fees.