Have you tried blogging with your students? Wesley Fryer discusses using "interactive blogs" in your class in this post. An "interactive blog" is one that allows posts from teachers, students, and blog visitors, but it is moderated.
Fryer has been working with educators and polling them this summer and discusses his findings in this article. He also links to an article, "Why Word Press? Class Blogging with Moderated Posts and Comments" which walks you through how to set up a moderated blog with Word Press.
Via Beth Dichter