Here are some educational blog sites that you might be able to use in your classroom.

Blogging tools:
to create free blogs
Http://manilla.userland.com
http://wordpress.com
http://edublogs.org

to up load documents:
to blogger.com
http://buzz.blogger.com/bloggerforword.html
to other websites
http://writely.com/

to create and host blogs:
Movable Type
http://www.sixapart.com/typepad/ Hosted Movable type

Other Blogger sites:
http://supportblogging.wikispaces.com/
http://www.blog-connection.com/blog-articles.htm
Http://kidzlog.com
www.21publish.com
www.teacherhosting.com
http://classblogmeister.com
http://davidwarlick.com/2cents/
http://landmark-project.com/blogmeister
www.nlcommunities.com
www.novemberlearning.com