Here are links to two short movies and a VRML animation of a four-legged walking robot.
This robot is a successor to an earlier version written as a Java applet. The earlier one contained a primitive model of the physics, which did not attempt to model the dynamics of the legs, only the body of the robot, and allowed unlimited friction between the feet and the ground. This version of the robot uses the Vortex physics simulation library produced by CM Labs, to accurately model the complete dynamics, including collisions and friction.