Daryl:
The good news is that there are X-10 switches designed to operate your ceiling fan with variable speed. It's called an inductive dimmer switch and will respond to 16 dim/bright steps that will control fan speed. The bad news is that they are a Decora styled switch. There aren't any with a rotating knob to the best of my knowledge.
Robert
RCI Automation
[email protected][Link: ourworld.compuserve.com]If you