Tutorial on stepper motors:

http://www.cs.uiowa.edu/~jones/step/

A online distributor with stepper motors and stepper motor drivers:

http://www.omc-stepperonline.com/

Everything for the motion control industry:

http://www.motioncontrol.com/

Machinedesign:

http://machinedesign.com/

News for Product Design and Automation Engineers:

http://www.engineeringtalk.com/

General engineering search engine:

http://www.globalspec.com/

Engineering Directory:

http://www.motionnet.com/

The local automation market place:

http://localautomation.com/

CAN in Automation GmbH:

http://www.can-cia.org/