Battle Royale High School was some kids cartoon that was released in Japan in 1988.
The movie Battle Royale isn't carried by any major retail chains or stores. Many people have to import it, and even after that, you have to make sure it's the right "region" DVD.
www.aznfilms.com is a U.S. based company that offers it for a good price. If you don't want to pay money to see it, it is available online, and last I checked...was on Kazaa.