My class at U of I Global Campus has introduced me to pbwiki.com, the world of free wikis. Each student in the class has to create a wiki for our background research and papers.
A wiki is a collection of web pages designed to enable anyone who accesses it to contribute or modify content (from Wikipedia). And you don't have to know HTML or web programming!
PBWiki is having a drive to adopt their wikis, so they have created an adoption website filled with presentations you can watch or share with your non-wiki believing friends:
http://drivingadoption.pbwiki.com/
In case you can't think of a reason to use wiki: Create a wiki for your class to share resources with one another. They will be able to collaborate asynchronously in the writing and updating of wiki pages. Then you can provide feedback to your students on the wiki as well.
Have a good wiki!