Written for college professors, this article is a good summary of using clicker technology in the classroom. Dr. Erping Zhu is the coordinator of instructional technology at the Center for Research on Learning and Teaching at the University of Michigan. Good list of references at the bottom of the article.This is a link to MikeW's blog archive 'clickers'. He has written a couple of posts that may be of interest to you.
Image credit: Ohio University Student Response System (http://www.citl.ohiou.edu/index.cfm?pageID=29) The links on the left side of that page is another good overview of the system.