When I was a kid (and I'm talking about 20 years ago here) I learned piano through the Suzuki Method, which is basically learning by ear. By the age of 8 I was winning awards and playing recitals, and never learned to read a note.
I'm not sure if the Suzuki method is still in use, or if you can find literature on it, but that may be a start.
*edit* Killer sig, btw. Dimebag was one HELL of a guitarist
