One of the more memorable images from the movies of the 1970s was that of anchorman Howard Beale in "Network" urg- ing his TV audience to open up their windows and shout: "I'm mad as hell, and I'm not going to take it anymore." Unlike Beale's frustrated viewers, Americans during the 1980s will acquire a powerful tool with which to register their dissatisfaction with traditional TV programming-one that will allow them, in effect, to vote with their pocketbooks. The tool is new v...