For now this is just a quick list of resources that explain electric motors. I have tried to include sources with animations…

animations, mostly
wikipedia: induction motor more links in article of course…
wikipedia: brushed DC motors
all about circuits
UNSW animations in physics
reliance electric, not so glossy, but good explanations.

Added on May 26, 2010…

Read this post and if interested all the links from this post:
How to Size a Motor for a Project and MORE

I found it very informative. The second post, by Jeremy Harris, defines the problem and offers simple and direct formulas to respond to the issues. Other posts elaborate. It’s a good read to understand sizing motors for vehicles.