Wilhelm Copyrighted?

Does anyone know if “The Wilhelm Scream” is copyrighted? The scream is found in many films, most notably Star Wars and Indiana Jones. Will I get sued if I use it in a film I’m making? Let’s say that I eventually want to make money from the film.

First hit on Google:

http://www.hollywoodlostandfound.net/wilhelm.html

As an archived product of Warner Bros. it undoubtedly is under copyright and needs permission to be used.