The secret to playing by ear, is understanding the 'relative numbers' for chords and melody. You then apply the appropriate playing pattern, to change the style you want to play in.
All methods in the DecPlay range help with learning to play by ear, especially FastPlay, SingPlay and ProPlay, which use ‘relative numbers’.
EarPlay is a course specifically designed to teach playing by ear.
Stage 1 is to learn to play piano using a unique written system (DecPlay) that mimics the playing by ear skills and once you can enjoy playing piano (which should be pretty quick), then Stage 2 is to learn to identify the music by ear, so you don't need the written song sheets anymore.
For stage 1, if you want to play accompaniment for singing, then SingPlay is the best method, if you wish to play solo piano without singing, then FastPlay is the best method
Check out some of the amazing results at AMAZING RESULTS HERE