ChordU - Extracts chords from any song, integrated YouTube.
Audioalter - Your online audio toolkit. A collection of easy-to-use web tools for all your audio files
Guitaa.com - Turn ANY song into chords, play along with interactive chords and diagram, transpose, loop, tempo control.
Transcribe - An online app that reduces the pain of converting audio & video to text. Saves thousands of hours every month for journalists, lawyers, students and professional transcriptionists all over the world, including researchers in Antarctica.
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
Tune Transcriber - Learn and transcribe music for free from your web browser (no install needed).