ArduinoFun has a how-to on building this simple two-servo Arduino walker that’s a great starter robot project for kids. The body and legs were ordered from Ponoko. Shawn of ArduinoFun writes:

My son is 11 and daughter is 5 and they really enjoyed doing this. I was amazed at my daughter already thinking of new ideas to do with the servos. For example she wants to put a princess doll on a servo and use the Arduino to make a music box.

Arduino Simple Walker