Well, I started when I was about 14. Then I wanted to play GnR, Metallica, and other music that I was into at the time. I spent like a year emulating before I got bored. Before then, I would go to the bookstore and pick up a Metllica songbook with tab. After I got bored, I went to the bookstore again, but instead of going for a songbook, I got a general guitar playing book (I think it was "The Complete Guitarist" as Sam said). That got me beginning to understand basic music theory. I got hooked and have since read a lot of books on music theory and different playing styles. I haven't really learned any songs in I don't know how long, but I can play along with any song within a few seconds of hearing it, and I can write my own music now. Theory is king. And after you've got your theory down, learning songs by other people is easier. Technique and theory are what I practice daily now. I only practice songs a couple days before performances.