You might also be interested in David's blog for educators 2 Cents Worth.
What Mark Ahlness said in his blog edtechblog about Classblogmieister:
So here's my testimonial, my sales pitch for Classblogmeister. First, it's not blocked. Next, it offers TOTAL teacher approval before any student post or comment on a student post (take that, MySpace fear mongers). Teachers can leave online feedback for students to improve their writing (like if they want to get it published) that is hidden from public view. Next, it's free (thanks to David W's generosity). It also has a very active list on Yahoo! Groups for sharing and problem solving. Last, I have never, in 25 years of teaching, seen a more powerful classroom tool for motivating students to write. Nothing else even comes close. It is the perfect blogging tool for teachers.