I thought I'd share something I'm working on: a native app virtual piano.

Features are:-
- Multi-touch. Up to five keys playable at once for complex chords.
- Multi-sampled, so each key is a real piano sample.
- Easy change between octaves, and can start at C or F key.
- 4 Octave.
- Animated keys really look like they are being pressed.

Should be available for download pretty soon, however.

http://www.ipodtouchfans.com/forums/showthread.php?t=37567