Fachords - Fachords is an online site that provides many resources that you can use to take your guitar skills to the next level.
MyGuitarTuner.com - Online microphone tuner for guitar, ukulele, violin and other instruments. Tune by ear or using the microphone of your device. It's fast and accurate algorithm makes it one of the best online microphone tuners available.
TrueFire - The Best Guitar Lessons Online Fast. Easy. Fun.
Metronomus - Powerful and beautiful online metronome
Gitarrero Beginner - Gitarrero Beginner is a multi-featured, and easy-to-use guitar school developed as a guide to help you learn guitar skills and play them comfortably.
LINGOT - Musical instrument tuner, LINGOT is a musical instrument tuner.