Copy from audio tape to Media Player

I have my wedding ceremony recorded on a cassette tape that is, just, 20 years
old. I'd like to digitize it to back up the tape. A friend said connnect the
headphone jack on the handheld tape player to the microphone jack on the back
of the pc. I can hear the recording through the speakers but nothing,
apparently, is being recorded on MP. I am using W98 and MP9. Does anyone have a
suggestion on how to get my cassette to record on my pc?

Thanks! Steve Ignots