• EduBlogs
  A blogging service specifically for education. If you already have blogging sites up at places like Blogger, TypePad or LiveJournal you can import your content straight into your Edublogs blogs.  
  

• Blogger
  Google's blogging tool that is easy to use. Recent improvements include more privacy features. 
  

• Class Blogmeister
  David Warlick's tool that facilitate blogging with students. "This online blogging tool is explicitly designed with teachers and students in mind, where the teacher can evaluate, comment on, and finally publish students' blog articles..."