Learn guitar/piano chords

A lesson where you connect a microphone to your computer. OpenTeacher asks you to play a certain chord, you play it, and OpenTeacher tells you whether it was good.
I made this little program: http://www.youtube.com/watch?v=Ff-V6ggv100
It's not hard to port that to Python if there's a good fast-fourier transform library for Python.
It's also not much of a problem to make the user correct his own answers of course, but it might be annoying to pick up the keyboard each time you play.