ChordU is described as 'Extracts chords from any song, integrated YouTube. It's all free with capo tuner and comes with two versions of chords for a song. Start playing along'. There are more than 10 alternatives to ChordU, not only websites but also apps for a variety of platforms, including Android, iPhone, iPad and Mac. The best alternative is Guitar Dashboard, which is both free and Open Source. Other great sites and apps similar to ChordU are Chordify (Freemium), UltimateGuitar.com (Paid), GUITAA (Free) and GtrLib - Guitar Chords (Freemium).