Arduino is a very popular processor that is allowing many otherwise normal folks to get into robotics and hardware programming. Here are some links to some stuff I found interesting.
Atlantic article which does a good job explaining what the Arduino is all about.
Blog article and video on making a programmable robot from a popular cheap kids toy.
Hacking a cheap digital camera for Arduino control.
Controlling a Roomba with an Arduino chip.
Make magazine's intro to robots.
MakerShed a source for Arduino processors and other related electronics.