Fender Players Club
Part online neighborhood/part lesson database/part guitar god fan site/part store, this site has it all. And despite the name, its surprisingly not devoid of Gibson players and mentions of other guitars in gear sections.
The lessons are especially good. PDF's detailed with backstory and instruction rife with links to mp3 sound clips, not streamed sound. And musical notation, plus tabs, plus recommended finger. Of course its just a sampling intended to sell you their books, but there's a lot to work on here.