I've been trying to find an adaptor that allows me to listen to a stereo cassete/MP3 player on a computer headset. The situation is thus:

stereo headset: two plugs: one headphone, one microphone.

--headphone jack (similar to top) has three metal strips and two black plastic separators
between the metal pieces.
--microphone jack (similar to bottom) has two separate metal connections and one black plastic separator.

MP3/cassette player has just a basic female TRS jack connector, 6mm, stereo. Like an ipod or stereo CD player.

Does there exist a commercially made adaptor that allows one to use such a headset to listen to such a media player? At all, it is not a problem if it requires its own power source. I know there are such adaptors, I just need to find one available on the electronics market.