mCircle is a free javascript online application. It was designed to assist the student in graphing structures over the circle of Vths and finding all possible subsets contained in a main structure, such as finding upper structure triads. mDecks

Circle of fifths in all 12 keys
A free downloadable pdf file. mDecks

All Guitar Chords - Chord finder, including split chords and chord variations. Also features standard and exotic guitar scales.

Twelvemonth Music - Learn Music. Learn to play guitar.

Guitar Secrets - Free Guitar Lessons, Lead Guitar Made Easy.

TAXI’s Music Biz FAQs contain songwriting tips music-business information, and articles on Film & TV Music placement.

Jazz Guitar Chords Books - Books in Jazz guitar chords for many different levels.

Music Theory Books - Recommended music theory books.