Making some doots.
Here's my piezo fritzing diagram:
I wrote all my songs in the Arduino Language. To figure out the melodies, I would watch youtubes of kids playing theme songs on their pianos. I knew how the notes corresponded to the keys and would just jot them down as they went. Typically they never played cords, so I didn't have to worry about that.
All of the code for these lives on github here