Write Design Online: Graphic organizers - explanations of various kinds of 
organizers with models.
http://www.writedesignonline.com/organizers/index.html

Teachervision.com - ready to print graphic organizers
http://www.teachervision.fen.com/lesson-plans/lessons-6293.html

Tools for reading, Writing and Thinking - Includes sample graphic organizers.
http://www.greece.k12.ny.us/instruction/ELA/6-12/Tools/Index.htm