Rockman 1-6 Famicom Music Collection
They sell a cd set with Megaman
songs from game 1-6 on this site. You might want to check it out. (It's expensive, but looks interesting)
that's interesting for sure, Megaman 2
had some of the best music on the NES in my opinion. I've been listening to the remixes of it for weeks.
Interesting, but a bit too expensive.