Chrystie,
Attached is a Word file with a few ALA links that address privacy and/or intellectual freedom in school media centers. They don't address the original question, which was a request for software that would allow the librarian to send messages and monitor sites the students are accessing. At my library, we use a product called SAM, which manages Internet traffic and printing (we use it in lieu of signup sheets). On SAM, I can send messages to users, but I have no way, fortunately, of monitoring their screens.
I work in a public library, and I know the issues are different than in school media centers. But no matter what kind of library you work in, it's important to have written and VERY accessible policies that spell out what is and is not appropriate and acceptable behavior, whether by patrons or on the part of the library. As you say, sticky stuff.
