Chordbook.com is a Flash interactive interface, which runs a rather extensive chord book/dictionary. Not only has it a list of the most used chords, but it contains a lot of chord variations from the most common versions up to those barely met such as the augmented ones. Even more, for each chord chordbook.com will also provide a large number of inversions! You can change the strum, strum speed, set up your own tunings and even set the starting fret (by using a capodaster) or switching between the acoustic and electric guitar sounds.
All in one, chordbook.com makes a very comprehensive resource for both the beginning guitarist and for the more advanced one seeking new chords or chord variations to enrich his/her style or generic play. The best thing is the combination of both visual and audio streams of information as it is common knowledge that this is by far the best way to have things well fixed in your memory. Chordbook.com also offers an online guitar tuner and – much to my pleasant surprise – an extensive set of audio-visual guitar scales. For those who are not that familiar with playing the guitar, scales are one of the most important ways to get to “know” where the notes are placed on the fingerboard of the instrument, so the mind will work faster and with significantly more freedom with each set of scales the player knows by heart.
An excellent source for learning to play the guitar. “What's so special about it?”, some of you might ask... the fact that it is freeware and anyone with internet connection can access it; and secondly (and in my opinion, even more important), the fact that chordbook.com offers more than a list of pictures with the note positioning on the frets. It’s quite useful and I definitely liked it!