you will need a 3.5mm 3pole (or 3 pin) male connector on the pc side which splits into two 2pole (2 pin) male connectors. the 2p side can also be called a mono 3.5m jack.
3pole side
2pole sides
it has a ground and only one of the audio channels
i'm having a very hard time locating a cable you can buy to do this. you would think its a common thing however it appears not. i'm sure its carried somewhere but i didnt see one in the 5 minutes or so i spent looking.
you could wire it up yourself by buying the 3pin, 2x 2pin jacks, some wire and soldering your own cable up then just wrapping the cable up to the point...