You might be interested in this site:
free mp3 downloads - Gameboy music & camera/ 8-bit futurist/ atari /micro-chiptunes/electro-funk/space-punk -ReceptorsMusic.com
It's mostly about Receptors, but there are a couple other different bands on there too. All of the music is made with circuit-bent GameBoys, Playstations, etc.
Also the band Totally Radd is worth checking out. They've changed their sound a lot recently but their stuff from about five years ago totally sounds like old Nintendo music.