The AP has an interesting piece on Carnegie Mellon's snake robots. The research, lead by Howie Choset, is aimed at disaster situations where a small snake could maneuver much better than a resuce worker.
"Right now, the way to get to these trapped survivors is to pull the rubble out one rock at a time," Choset said. "So our dream is to have the snake robot thread through this collapsed rubble and get to victims more quickly."
The robots are semi-autonomous, and are remotely guided by a radio controller. They are controlled with servo motors and battery powered. The Snake's website, shows video of them crawling in a sinusoidal motion, rolling, swimming, and crawling through pipes.
Unfortunately, Choset says the robots wont be ready for prime-time for another 5 to 10 years.
Another prominant snakebot builder is
Dr. Gavin Miller. You'll also want to check out
this amazing amphibious snakebot from Japan.