A great explanation of how musical notes relate to math

I've often wondered about this, but only got so far as to deduce the 12th root of 2 as a factor.

http://math.stackexchange.com/questions/11669/mathematical-difference-between-white-and-black-notes-in-a-piano

This link also, is chock full of awesomeness:

http://www.maths.abdn.ac.uk/~bensondj/html/maths-music.html