Hi Ron,
What I normally do is that I take a cable, which supports stereo of course, and plug it in the Stereo-Out and link it to the Line-In from my soundcard. Before this, I had recorded the desired songs that I wanted to convert in midi on my keyboard. Then I take a good recording program on the computer and record the line-in from the soundcard while playing a midi file which I recorded. Edit it a little by cutting the silenced parts away and there you are, the song is now on the computer. Then you need to find a program which supports saving audio in MP3. A good example is Cool Edit which I use frequently. Then you're done.. And you can do with it whatever you were up to.
Happy holidays,
Sander
The Netherlands