This year I´m using Wikispaces as a classroom program. Something totally new for students and I hope they take advantage of this tool.
Take a look at the presentation given by Viki Davis on Wikis. It´s very complete and a good resource if you are planning to add them to your classes this year.
Watch what educators have to say about Pbwiki.
I created a new Open ESL Classroom blog. The idea of this blog is to communicate with students after class and to get to know each other better.