What is the best music theory app for iPhone?

One that includes tutorials on different aspects of music theory, includes ear training, and sight reading.

I don't know any apps, but there's this website my chorus teacher tells us to go on to practice… It's called musictheory.net or i think it's.net, I'm almost possitive, but you can search that on google… On the website you can choose levels. The beginner is basically just showing you the notes on a staff and you have to say what note it is. It will get harder the higher levels you go though

Music Theory Pro - the developer just launched a new version for mac computers but the original iPhone version is pretty cool too. Great for drilling note namces, intervals, chords and scales on the go.