LOS ANGELES -- The filmmakers of "Left Behind: World at War" figured a little preaching to the choir would help market the Christian-themed thriller. They preceded the movie's DVD release Tuesday with screenings at about 3,200 churches across the United States and Canada, hoping to build word-of-mouth for the straight-to-video sequel in Kirk Cameron's series of films about Armageddon. Cloud Ten Pictures, which produces the "Left Behind" movies, did not yet have attendance estimates on how many people caught "World at War" during the weekend screenings. But the company went into the weekend projecting as many as 1.8 million people...