Code Studio (ages 5+)
These courses have been developed by code.org which is a non-profit organization providing the opportunity to learn computer science. Code.org is supported by generous donors including Microsoft, Facebook, the Infosys Foundation, Google, Omidyar Network, and many more.
Scratch (ages 8+)
"Scratch Programming Playground teaches you how to program in Scratch, the graphical programming language from MIT for ages 8 to 16. It features 8 game and art projects. "
Download the book Scratch Programming Playground