So you would like to build your own snake robot? The Lake Erie Mamba project shows you how to do just that. It is all about building a reconfigurable robot snake with different modes. The snake has 12 segments actuated by servo motors. It has inch worm, slithering, rolling, and other modes of locomotion.
You are going to need an Arduino Mega, 4 button remote control keyfob, 12 servos, 12 LEGO wheels, a battery, sensors, and a few other parts to get started. More info is available here.