http://www.coedu.usf.edu/~morris/coopsss.html
This site has cooperative learning lesson plans organized by subject area.  It provides teachers with good models so that they are more able to think of their own lessons incorporating cooperative learning.

http://sps.k12.mo.us/coop/ecoopmain.html
Created by educators in the Springfield, Missouri Public School System, this site focuses on collaborative learning in the elementary classroom.  It offers a variety of detailed K-5 lesson plans that utilize cooperative learning activities.  Lessons are arranged both by grade level and by subject area.