CGHS got 51 new MacBook Airs this year, and those of us in the library are in the process of setting them up and rolling them out. Don't worry, we didn't throw them all away. No Airs were harmed in the making of this blog post.
Robotics Demystified is intended to be a guide for beginning designers and includes lots of diagrams. The material is broken down fairly well, and the book includes information on everything from gears and sprockets to capacitor networks. The information on mechanical systems is particularly helpful.
Another useful resource on robotics is the GoRobotics blog. It includes tutorials, tools, projects, and inspiration.