A Tampa, Fla., Web entertainment firm has filed suit to put the kibosh on CBS' 'Big Brother,' claiming it's being skinned by the voyeuristic TV series. In a suit filed in New York federal court against CBS and Infinity Broadcasting, Entertainment Network claims Infinity execs stole "trade secrets" from a voyeur-TV concept they discussed during a couple of sit-downs in August 1999. A CBS source suggests the suit is just an attempt to attract publicity for the VoyeurDorm.com. Web site. CBS calls the suit "frivolous" and the allegations "ludicrous" in a terse statement issued Wednesday.