So I found a free application called 8-Bit Era Soundboard. It has 9 NES songs (super mario, castlevania, zelda etc...) and it lets you use them as ringtones or you can just play them. Anyway, how is this legal? Are those songs open domain or something?

Or is it just legal because he's not profiting from his app? (actually his app has an Ad... so he is profiting I think?)

Here is an article on the legality of Nintendo ROM's:

http://www.nintendo.com/corp/legal.jsp#roms

Not sure if you can encompass the music under this. It basically says ROM's are copyright for 75years

that's really odd because I see a bunch of old NES games on the android market for free. WTF? How can google approve illegal material?