I made a headphone socket conveter fom a cheap mini radio i got out of a pound shop and the handsfree that came with my fone. the mp3s sound quite good when you connect your normal headphones into it. if you want more info just post a reply with your questions.
well youll need a soldering iron some solder the cheap radio or something that a headphone socket and a handsfree
1. take the radio appart
2. find the headphone socket and take it out i did it by just breaking it off
3. take off any remaining circuit board
4. cut the connector end off the hands free leaving about an inch of wire an take the plastic bit off the connector.
5. seperate the wires leaving there plastic coating on the power supply one but take the plastic coating off the audio one which usually is red blue or green
6. split the audio one into two and twist the wires.
7.now youve got the two things you need all you have to do is solder them together.
8. on my headphone socket there were three pins one at the front (power part) and two pins at the back (audio part).
9. ijust soldered the wires in there correct places and taped it up.
10 make sure no wires inside are touching as it will not make the phone think its a loopset or headset.
to connect up just plug the converter in the phone first and plug the headphones in the other then off you go and listen to all the mp3 and ogg formatted music you want it works on voice calls to although youd need a microphone on the headphones that could be my next project.