you can do it just with windows sound recorder...it's how i got cadaveryne onto my IPod haha
you have to go into the recording properties of the volume controls and mute everything but the wave balance...but it'll work.
if you just want something you can listen to on your comp or to burn to a cd, it saves as a really high-quality WAV file(it kills tons of space, like 50MB per song...but you can go into the audio properties in sound recorder and switch to different bit rates)
if you want to put it on an IPod...you'd have to get a WAV->MP3 converter, but those are easy to find and use