Oolimo.com | Guitar Chords
www.oolimo.com
The interactive guitar chord compendium. Learn to understand guitar chords. Multi-functional chord diagrams, chord finder and analyzer (chord namer), chord types and chord progressions in pop/rock/jazz, quizzes on guitar chords.

I really enjoy this site, it has helped me learn a lot. There’s a lot of useful tools, I especially like the chord analyzer.