Student Blogging and Web Safety and Security

I would like to start blogging with students this year (starting with my posts that they respond to and moving into them making the posts themselves). I have seem examples in many different formats. I know that my district will not let me use any program that asks for student emails. I already know not to let students use full names; first names and last initial or some other code instead.

I need advice on what program to use and how to set it up so that my district will think it is safe and secure. I know that these are touchy terms, but at this point in time I want to work with thier policy and not fight it. Can anyone help me with advice and/or site reccomendations?