There seems to be no end to the methods available for hacking R/C servos for continuous rotation. Dale Wheat of the Dallas Personal Robotics Group has put up a web page detailing his servo hacking method, which has the advantage of being really simple. He recently did a live demonstration at a DPRG meeting in which two volunteers from the audience hacked two servos live as he instructed them. Using only a screw driver, wire cutters, and a drill, both volunteers succeeded on their first try. In the past we've covered the SRS servo hacking method, our own Swirling Brain's Sub-micro servo hack, and others.