Isn't it a bit hard to take a GBC and get music from it onto the computer?
Not really, in fact, it's the easiest out of all video game recordings. Just get a speaker cable, plug it into your headphone jack, and plug that into your line-in port on your sound card. No special adapters needed or anything.
I did it for Link's Awakening for a little while, but then when I was doing it, a recording by someone else popped up on Galbadia Hotel.
Oh, and I've also done a little bit of Virtual Wario Land, but like 10 people have played the game, and I've only recorded about 15 or so songs, and some of them are riddled with sound effects, so I'm probably going to just keep them to myself.