http://www.jigsaw.org/
This site presents the jigsaw method as a cooperative learning strategy.  The official site of the technique's founder, this web page provides background on the work of Elliot Aronson and on the circumstances surrounding the development of the jigsaw.  Users may explore the benefits of this process and view a step-by-step guide to implementation.  They can also access other materials and websites related to the jigsaw technique and cooperative learning.
 

http://ericae.net/db/edo/ED306003.htm
This document focuses on the use of cooperative learning in the primary grades.  It points to research and the work of theorists such as Johnson and Johnson, Glasser, and Slavin to describe the long-term advantages of collaboration.  The article provides steps for teacher implementation and the titles of books that contain more information.