A former religion teacher at the Westchester Day School in Mamaroneck who pleaded guilty to possessing child pornography -- including videos he had gotten mailed to the school where he worked -- will be spending some time behind bars. Lyle Kamlet, a Mount Vernon resident, was sentenced Tuesday to three years and three months in prison by Judge Kenneth M. Karas in federal court in White Plains, according to Preet Bharara, U.S. attorney for the Southern District of New York.