Chagrin:
Couple more links: http://www.openservo.org/ (see: http://www.openservo.com/StepByStep) and http://code.google.com/p/zosupermodified/These designs are intended to replace the control board inside an RC servo to give it full positional feedback. The "openservo" hardware is available for purchase but the "supermodified" hardware appears to have fallen off the internet unfortunately
Thanks, I bookmarked all of them for later use. There is clearly much I don't know and I need to read the existing documentation. (Yawn!)
Lou.