Except, in my school district at the very least, they are allowed to block access to certain sites, Myspace among them, as well as Google's image search. The problem is, there's plenty of precedent for the restriction of free speech in schools if it is deemed disruptive by the administration. What they deem disruptive usually seems rather arbitrary to us students, but there's not a lot we can do about it. (Of course, considering the amount of time some people spend on Myspace...)