Cyberfret.com Guitar Lessons - Free online guitar lessons using audio and video. This site also features a tablature section and links to many guitar and music resources.
Guitar Lessons at Guitar MX - Guitar lessons and tools for beginning and intermediate guitar players.
GuitarWiki - Exactly as the name implies, a guitar related site where anyone can contribute their knowledge.
Pignose G40v Mods - This is a link to an article at blueguitar.org which includes a bunch of mods for the Pignose G40v tube amp.
Harmony Central Musician Community Forums - In my humble opinion, the best online musician forum with liberal moderators and a variety of sub forums covering any and all musician related topics you can think of. Highly recommended.
Music Virtuosity - Free guitar video lessons from professional guitar instructors for all levels.
Lastminute Auctions - Site listing eBay auctions with less than an hour left with a price less than $1. The link will bring you to the guitar category.
goingTODAY.com - woot style site with a new musician oriented deal everyday.
MojoCaster.com - Guitar based community featuring reviews, interviews, videos, lessons, and more.
TheStompBox.net - Forum dedicated to guitar effects with a strong emphasis on multi-effects processors. Be sure to check out the in-depth and pratically legendary “Head to Head MFX Shoot Out” by Kewlpack.