Don Bluth's "An American Tail" is based on the story of a young Russian mouse who is separated from his family in America and who later heads with his reunited kin out to the American West. It's pleasant, though not spectacular, and has its greatest problems in story development. Steven Spielberg produced with an eye toward creating animation hits outside of Disney, and he and Bluth certainly took a big step in that direction here. Kids like it a lot, and adults will warm to the sound of various familiar voices, such as Dom DeLuise as Tiger and Madeline Kahn as Gussie Mausheimer. It's also the source of the pop single "Somewhere Out There." -KENTFLIX