Let's Make Music
Betty Hughes is an independent Baptist preacher's wife, and has taught her Let's Make Music course for many years. She has taught this program in seminars, as well as one-on-one. The tape and book combo are among the best resources that I know of for aspiring church pianists. She begins simply, but eventually covers areas such as chord and scale construction, left and right hand technique, and general playing tips. My favorite parts of the tape are when she just plays... and plays she does! Many times there is a split screen showing her as she talks to you, as well as the keyboard she is playing on, both at the same time. For $54.00 (last time I checked), this is one of the first items I would purchase, for while other courses teach either a jazz or classical style of improvisation, she teaches what we would definitely refer to as the Evangelistic Style!
As a plus, this course is now available on DVD.