The Guitar Tools site has a host of lessons on how to play guitar, including

1) The ultiamte way to practice guitar
2) Sweep picking and tapping
3) Chord directory
4) Tuning guides
5) How to solo
6) Fretboard to notechart
7) How to read tab
Two hand tapping

They also have a reviews section which reviews guitars, amplifiers, effects etc.

Rankings

Overall   (5 out of 5 by 1 users.)