PianoNanny.com is offering free on-line piano lessons:
Your instructor for the course is film composer and jazz musician, Clinton Clark. Each lesson takes about 35 minutes to complete. However, work slowly and at your own pace. It’s important to learn each lesson before moving on to the next.
They give an excellent summary of jazz in:
Jazz is a shared learning experience. No person learns the art of Jazz without playing along with other Jazz musicians. One learning tool for doing this is to play along with recordings of other Jazz musicians. There are courses of studies that use recorded jazz groups leaving out one instrument. This one instrument might be a piano part, bass part, trumpet part, etc. Then, it is up to you and your instrument to fill-in the missing part.
they play if you go to that lesson (it’s a MOV file with just sound).
I’ve been playing the piano for around 25 years and still can’t “get” jazz, can’t get in the grove. I love listening to it and envy those who can improvise. I think I may see if these lessons help.