Socrative Website: http://socrative.com/
Students can use a variety of mobile devices to answer questions at: http://www.m.socrative.com
Teachers can open t.socrative.com and set up a classroom. You can then ask multiple choice/true-false/short answer questions verbally and when students answer, a graph of their collective responses appears on your iPad or other mobile device).
Web 2.0 Survey and Polling Tools
Web 2.0 Survey & Polling Tools: A Quick Guide
A guide to survey & polling tools.