General Motion Control and Automotion Sites On Line

Automation Forum is a "diverse group of industry leaders dedicated to advancing the understanding, use, and benefits of integrated, flexible automation - the broad spectrum of manufacturing technologies, from computer-aided design to production and automated warehousing, and the contemporary management systems necessary to run today's businesses."
http://www.automationforum.org/

Basis of Motion Control is an excellent introductory tutorial by the editors of Machine Design magazine. Topics covered include the basic types of motion control, position components, loop variations, filtering, etc. There is also a section on motion controllers and counters.
http://www.machinedesign.com/bde/motion_control/index.html

Motioncontrol.com provides information about the latest industry news and events, a motion control forum, and company and product search pages.
http://www.motioncontrol.com/

Motorcontrol.com features "hot" news and press releases, product and supplier search, motion and motor control communities, a discussion forum, expert advice section, career information, classifieds, and a bookstore.
http://www.motorcontrol.com/