Acoustic Guitar Central - guitars & gear, guitar lessons, makers, guitar magazines...
Guitarist Heaven - guitar lessons, interviews, transcriptions, reviews, picks gallery ...

Guitar principles - Welcome to the home of guitar principles & "The principles of correct practice for guitar"! - where those who play guitar come to achieve excellence..... - place for players, resource for luthiers
GheesyGuitars - Guitars, basses and effects from the communist era
Celtic Guitar Music - Glenn Weiserīs homepage ( fingering guitar, harmonica, celtic music, blues) - Celtic guitar books, solos, lessons ... - home recording, digital, mixing, tutorials ...

Exar electronix - "the production of our guitar analog effects is based on the hand-made installation exclusively - each one is checked individually"

The MIDI guitar and gear:
Troubador Tech - MIDI Guitars: A nearly complete roster
Midi guitar - the MIDI Guitar Unofficial Internet Home Page - guitar scales generator
Chord House - chords, scales, alternative tunings, sound