We have a few Universities here in Perth trialling and using TurningPoint in their courses and doing research on its effectiveness in both large and small group environments. There have been a few books published both here and over in the United States on the same topic.
Here are two that are available on (in preview) Google books
Teaching with Classroom Response Systems By Derek Bruff
Audience response systems in higher education By David A. Banks, Idea Group Publishing
So if you are interested in how others are using Audience Response technology, I recommend that you have a look at these.