Well, there are always alternatives to the actual sheet music.
MIDI files are computer generated music files, for them to work, the computer needs notes and chords entered by someone.
You could therefore use something like 'Noteworthy Composer' to open a midi file as a manuscript document... therefore it would be the music to whatever song the midi is.... though you are likely to get all the instruments and maybe the part you want is split over a few lines, but not normally.
Dunno really, its maybe what you want, but its a hassle at times.
Alex