When I found out about a program; COM-port Winamp that could control the mp3 player win-amp through the com port I set out to make my own control panel. The wiring diagram is even included with the program.
Here's what the panel looks like.
Here's where I attached the wires from an old serial cable.
Then I ran the cable out and plugged it into the serial port!
Now I can play mp3s without using the keyboard or mouse.
If you enjoy playing around with using the comm port to control your computer take a look at Termie: A Simple RS232 Terminal.