Behind The Notes

Those strange music notations always made me curious. How is it possible "write" the music? Will I ever be able to read these notations and play a piece? Can I jot down the notes of GNR's Sweet Child Of Mine while I hear it? I read that some of the masters never really played few of their creations - it was all in their minds and then in to paper! Check out the books to get you started: Piano For Dummies and Basic Music Theory : How to Read, Write, and Understand Written Music