Update:
I haven't had a chance to read
the opinions yet, but apparently the Court, by a 8-1 vote (Thomas dissenting ) held that the search was unconstitutional, but by a 7-2 vote (Stevens and Ginsburg dissenting) held that the status of the law at the time of the search was sufficiently unclear that the school officials are entitled to qualified immunity from suit. (The question remains open as to the liability, if any, of the district itself.) Souter wrote the majority opinion.