There are a couple of decent online resources at these links:
www.ultimate-guitar.com
www.olga.net
I am by no means a guitar hero but I found the best way to learn was to try to figure out how to play songs I really like. It tends to get you more involved and when you're doing it the right way, you know - because you know the material already. What's your favorite band? Pick a couple of their easier tunes and work on those, and pick up the harder ones as you go.
Or, just learn Beatles songs.
edit: apparently olga got oinked. ts.