Jody's comic book introduction to Arduino (which is licensed under Creative Commons) then tells what use you would have for Arduino, covers Ohm's law, explains alternating current versus direct ...

Educeeno is an arduino-based learning tool complete with tutorial book, designed for providing an easy path to learn more about electronics, and programming micro-controllers.

10 Simple-But-Fun Projects to Make With Arduino John Boxall, author of the new book Arduino Workshop, shares a few of the projects from his book on how to get started with the microcontroller.

It's also complemented with a host of online resources that even without the official Projects Book from Arduino, you can start building all sorts of projects.