Here are some resources to help you understand claymation techniques.

Introduction to Claymation
http://library.thinkquest.org/22316/trythis.html

Claymation overview
http://en.wikipedia.org/wiki/Claymation

Excellent student designed site with lots of information about Claymation.
Includes lots of samples of student work.
http://www.pwc.k12.nf.ca/projects/claymation/whatisclaymotion.html

Claymation - how to materials
http://library.thinkquest.org/25398/Clay/ClayHowTo.html

Student examples of Claymation projects.
http://www.dbprescott.com/claymation.html

Gumby World
http://www.gumbyworld.com/gumbysgalaxy/video/robot5.html

(Nortel LearniT, 2006)