We love Starfall website for the great free reading program. However it use flash, means it doesn't run on iPAD. Fortunately, with the help of a free app, you can access the website - fully functional like on computers
Top Ten FREE Online Phonics Resources for Preschool, Kindergarten and Beyond
Space: A Week-Long Solar System Unit for Kindergarten and
Starfall is a fun learning website for preK to grade 2 kids, but won't function on iPad iPhone.
10 Free Learning Websites for Kids. My kids have gone on some of these and they are great learning sites! - Kiddos at Home