Search the Opinions of the Supreme Court: Copyright
The Cornell Law School Legal Information Institute site has this nifty search engine, and so it's a great way to churn up all the decisions one might want to study regarding copyright. This Cornell site in general is terrific for copyright law, but I think this particular feature is worth highlighting, since it's neat and quick.
http://supct.law.cornell.edu/supct/search/index.html?query=copyright