ABC Learn Guitar – Free beginner guitar lessons, plus tips and resources on buying a guitar, songwriting, recording, and creating a music career.

Cyberfret.com – Free online guitar lessons using audio and video. This site also features a tablature section and links to many guitar and music resources.

CyberfretBass.com – Free online electric bass lessons using audio and video. This site also features a tablature section and links to many bass and music resources.

TabVoyage.com – Guitar and bass tabs, tablature resources, and lessons.

GuitarLodge.com – Online guitar and bass community with forums, lessons, tablature and music resources.

the-music-directory.com – A collection of links to music related websites and newsgroups.

How to Read Guitar Notes – Learn to identify the notes on the guitar in this free mini-course.
Also covers music notation basics.