A free 39-week e-mail newsletter titled "Piano Chords & Chord Progressions" is being offered by
Keyboard Workshop of Medford, Oregon. While it is designed for self-motivated adults, they feel it could also be useful to younger students who may be taking piano lessons, but need supplementary material on chords and chord progressions.
The newsletter covers the entire gamut of piano chords from "the 3 chords you absolutely, positively must know", to minor chord construction, extended chords such as 6th and 7th and 9th and 11th and 13th chords.
It also covers chord progressions - the way chords move in a song - from the standard progressions of a popular or classical song to the specialized progressions used in jazz, the blues, and gospel music piano playing.