I highly recommend Pauline Hall’s beginners piano books as a starting point. They are very clear and easy to understand.

For younger beginners, Tunes for Ten Fingers & More Tunes for Ten Fingers

For older beginners, Piano Time Book 1 & Piano Time Book 2

For repertoire, Piano Time Jazz

I also recommend the “Jazzin About” series by Pam Wedgwood – Really Easy Jazzin’ About & Easy Jazzin About

For slightly more challenging repertoire for beginners with a great application of blues & jazz techniques, try “Prelim 1” & “Prelim 2” by David Hellewell – available here: MDMusic.com (One of my early inspirations and a fantastic composer & teacher – David Hellewell’s piano music is unlike anything else out there. Covering Jazz, Blues, Latin and Rock styles, MD-Music is an ideal starting point for young pianists looking for a detailed introduction to popular piano techniques. My training with David and his wife Monica helped form the foundation of my playing style.)