well, i bought myself a xaphoon lately, which is kind of a pocket saxophone and right now i'm struggling to learn how to read the musical notes and how to get them played with the instrument.
i threw a little patch together which helps me get started.
it includes only the basic notes of my instrument, but for now it's ok, maybe i'll upgrade it sometime.
maybe someone here starts playing an instrument, too, so he could transfer/tune the patch for his instrument.
it's also very expandable: i guess it wouldn't be too hard to programm a song which you would play along a la guitar hero (also with gem maybe). you could even program it to write down the notes (pitch and even length in the notation system)if you play something freestyle.
if someone makes more of it, please share with us, thanks!
ps: you need a microphone input of course