DAVID KEHR writes: As the residents of Narnia like to whisper, "Aslan is on the move." And so he is. But for the moment, Walt Disney Pictures has him on a very short leash. Aslan, a talking lion with mystical powers, is the central figure in "The Chronicles of Narnia," the much-beloved seven-volume series of fantasy novels written by the British academic C. S. Lewis in the 1950's. By the year's end, if Disney marketers have their way, he will have joined Mickey Mouse, Pinocchio and Buzz Lightyear in a long line of characters that have periodically provided the Burbank giant with entertainment's most valuable asset, a new fantasy to trade on. [More]