Well, one of the best books I read was this:
http://jamorama-leadguitar.blogspot.com/
it’s actually an eBook, and it costs money (not much), but then again, it’s not an ongoing payment like guitar lessons would be, so who knows…
Christmas is coming up, ahah.

But as far as free things, I’ve found these websites helpful:
http://www.ultimate-guitar.com and http://www.cyberfret.com

A good book is nice to have though.

Oh, and Cyberfret might be .net instead of .com. I don’t remember it’s been so long.
References :