Nickelodeon network brings another of its animated kids series to the big screen, pumping up the gentle, good-neighborly lessons of the originalpolite manners, cultural tolerance, etc.with a maximum dose of plot steroids. The titular hero with the squashed oval for a head (voiced here, as on TV, by Spencer Klein) must rally his friends, family and neighbors to oppose a nasty old developer (Paul Sorvino) who wants to raze their quaint hamlet to build a giant "mall-plex." If the plot sounds formulaic, its been borrowed from those Kurt Russell college movies that Disney made in the early 1970sThe Computer Wore Tennis Shoes, Now You See Him, Now You Dontand in which Cesar Romero always played the evil industrialist. This would be as innocuous as those flicks without its post-modern references to Speed, Men in Black, The Incredible Hulk and All the Presidents Men or without the secret weapon of a way-cool spy chick (Jennifer Jason Leigh) to help Arnold and his friends save the day.