I haven't heard of any Mario game music being published commercially, but you can print out your own sheet music right in your own home! (Yes, you can!)
First download a freeware/shareware MIDI sequencing program that displays music in sheet format. I reccomend 'NoteWorthy Composer'. Then get ahold of some MIDI songs you like and open them with the sequencer, and simply print out the sheet music.
I am a musician, and I find sequencers like this to be especially helpful for writing out original, professional-quality sheet music.