Facebook: My guide to setting up groups; Facebook's guide to setting up groups; Tips for using Facebook as part of class
Twitter: My guide to using Twitter for education; Twitter tips for academics; 100 ways to teach with Twitter
YouTube: My guide to sharing YouTube videos; a guide for educators using YouTube; Overview of the new YouTube education site.
WordPress: My guide to setting up a WordPress blog for your class; Chronicle article on benefits of WordPress as a learning management system
Google+: My brief guide to using Google+ for education; Google's more extensive guide to using Google+ for education.