Free Classical Sheet Music in .pdf format with demonstrational videos
Though not very pretty, this site has a great collection of free jazz piano lessons and an active community. Of course, it's also free.
Free Piano Lessons with playback and diagrams
Practice you piano recognition skills with these exercises. Teachers can also customize the assignments and get students to send them results.
As you might guess, these are free online piano lessons
Free interactive Piano Lessons
Free Lessons from Berklee College