WordPress MU

I am a high school teacher and I am considering setting up a WPMU blog system for my students to use. I want to be able to approve their blogs and comments before they are posted. I know that WPMU can set up admin approval of comments, but can a WPMU admin also approve all users' blog posts before they go up?

Post moderation? Yes. Here's how I do it. Drop the following into mu-plugins:

<?php
function ds_moderate_all_posts($post_status) {
get_current_user();
	if (!is_site_admin() && $post_status == 'publish') {
		return 'pending';
	} else {
		return $post_status; }
}
add_filter('status_save_pre','ds_moderate_all_posts');
?>

SiteAdmin visits each blog to approve those posts, however. I use Donncha's Sitewide Tags on the main blog to generate the sitewide "Posts Pending" list.

You could set all users to "Contributor" role at signup as well via a plugin: see Roles and Caps if that's an option.

Make sure each blog has comment moderation turned on: New Blog defaults can help there, I use a $whitelist_options filter of my own to set/lock selected users options via plugin after that. Tracking comments from unregistered users is impossible. Tracking Registered users comments needs a plugin. Pings/Tracks are hard to stop without disabling these features completely.

I also use a Menu plugin to more easily control what menus users see in their admin side as well.

Andrew Billits has a very nice moderation plugin at http://premium.wpmudev.org/project/moderation

That's a lot to do in a couple days.

Here's what I'd do first:
Set each user as Contributor or Autor on their blog, raise them to Admin later. Set default settings using New Blog defaults plugin.

I also prefer to use a Privacy plugin to keep blogs, well, private. If knuckleheads are given a "private blog" I can set privacy option so I am the only one to see the blog at all - moderated or not. Privacy plugin code has a optional note to keep the entire WPMU visible to campus users while on campus only.

My install at school isn't foolproof, but I've been at it for a while now. I have a few plugins kicking around to lock down it all if I need to: inappropriate tagline filters, incorrect gravatars ratings, bad word filter, hotlink image protection, comment tracking, author switching, nasty header images etc etc.

Oh, I also moderate blog creation as well.

Oh and a new Post Lock plugin I'll try this semester.

Have you considered a turn key set up from http://edublogs.org ?