They are MIDI files. You'll need some sort of music program that can read MIDI and put it out into notation for you. There's a lot of programs you could use for that, but if you want something you could get for free then just look up Power Tab on google and download that. It's a neat program...useful for reading MIDI's and also for arranging music of your own (you can get the whole band going if you learn how to work everything right).
I use Guitar Pro for that kinda stuff, but you can't download a full version of that for free, and the demo is quite limited, so Power Tab would probably work better for you.