For the first time, cable subscribers will be able to watch movies on the same day as they are released on DVD as a result of a deal between Comcast, the nation's largest cable company, and several major studios. Comcast is currently testing the video-on-demand (VOD) service in Denver and Pittsburgh, according to published reports appearing today (Tuesday). The trial began quietly on Nov. 28 with little hoopla in an apparent effort to avoid a clash with DVD rental giants like Blockbuster, which have heretofore enjoyed a window of at least a month between the time films are released on DVD and the time they hit cable for on-demand viewing. Bruce Leichtman, who heads the Leichtman Research Group, told the Denver Post that the same-day VOD service represents "the ultimate convenience of not leaving your home. It's not movies over the Internet but straight to your TV."