Andrea & Scott: Thanks a lot for your replies, they are a great help.

Andrea: I agree with you that listening and analizing songs from great players are an excellent method of making progress in understanding harmony. It requires a lot of time (like many good things in life!) but the rewards are important. In a brief search in the web I found this software that can be an interesting tool to study songs: http://www.reedkotler.com/

Scott: Your comments confirm the good opinions I got from friends at a portuguese jazz school about the "Jazz Piano Book", by Mark Levine. I will surely order it. Two other (less known?) authors caught my attention: Debbie Denke [ http://www.debbiedenke.i8.com/ ] and Conrad Cork [ http://www.tadleyewing.co.uk/ ]. Debbie Denke also wrote a book called "Amazing Phrasing Keyboard". These may be more practical books. I will also check these.

Thanks again to both of you

-- José.