Ok, I know it's illegal to use someones song in your game without paying or getting their permission (like say using a Guns and Roses song or something). But what about those free midi songs you can get on the internet that have the same beat and everything as the song, just no singing, and it sounds different...well because it's a midi. Are those free to use in games, or would you still have to get the artists permission (by that I mean would I still have to get Guns and Roses permission?). I assume I would also need the permission of whoever created the midi. Thanks

There are two problems with using copyrighted music in your game. First of all is that the actual recording (consisting, say, of Mariah Carey singing) might be copyrighted. In the case of a MIDI, it's possible that the person who recorded it has granted people permission to use it; you should check with them. The other problem is that the song itself may be copyrighted by whoever originally wrote it (probably NOT Mariah Carey). A MIDI of a well-known song will almost certainly be copyrighted in this manner.

Bottom line: Don't do it.

Long story short: find a composer. Everybody wins, your game gets its own style, and some composer gets to work on a project.