I have recently launched a completely unique product which is a drum teaching app for the iPhone, Mapex Drum Masterclass.
The idea of the app is to learn to read drum music while on the move, using the on screen snare drum to practise the patterns. It's aimed at beginner drummers, or those who have never quite managed to learn to read the music theory and musical notation. Please check it out http://www.mapexdrummasterclass.com
I'm always looking for feedback for the app, and everything that has been said about the app so far has been very positive.