GT Post Approval adds “Approve/Reject” buttons visible just for administrators and editors in the Menage > Posts page. Not approved posts are visible just in the author’s archives and in the search results.
When you install this plugin any old posts will be approved and any new post will have to be approved.
This plugin is been made for the SEO contestants of GT GlobalWarming Awareness2007 and also for this reason the plugin has “static” features.
To make it more flexible I’ve developed the version 0.3. It’s a beta but it seems working fine. So in the version 0.3 the admin can go to Options > Approval to choose where display not approved posts and to define an user level to auto approve posts.