Wikisimpsons - The Simpsons Wiki
Rainier Wolfcastle was chosen as the star of the film, although a producer suggested Dirk Richter, star of the teleivision series, despite the fact that he was dead. The producers needed to film it in a location that had a nuclear power plant and a gorge. They chose Springfield, assuming it had to be a good place because they ad found in Variety was small and incorrectly spelled (as "Flim Springfield").
Mayor Quimby and Chief Wiggum were excited that the film would be shot in Springfield, vowing that they would do whatever possible to help the film. However, they, along with the rest of the town, started gouging the film producers for as much money as possible by levying new taxes and charging exorbitant prices for goods and services.
The producers began an exhaustive search for the child who would play Fallout Boy. A number of children, including Bart Simpson, Nelson Muntz and Ralph Wiggum, auditioned for the role before Milhouse Van Houten was chosen. However, Milhouse did not like being a star, finding the repetitiveness and phoniness disheartening. He eventually ran away from the production, just as the most expensive scene in the film was being shot.
Mickey Rooney tried to convince Milhouse to return to the film, but was unsuccessful. Rooney tried to play Fallout Boy himself, but the producers decided to shut down production, since they were broke from the townspeople's gouging.