HEAT oven to 350°F. Coat 13x9-inch baking pan with no-stick spray.
MIX together graham cracker crumbs and margarine with a fork until evenly moistened. Press evenly into bottom of prepared pan.
BEAT cream cheese until smooth using an electric mixer. Gradually beat in sweetened condensed milk. Add eggs, lemon juice, vanilla and flour. Mix well. Pour over graham cracker crust.
STIR jam until smooth. Drop by small spoonfuls over surface of filling. With a knife, swirl jam gently through filling to create marble effect.
BAKE 25 to 30 minutes or until center is set. Cool to room temperature. Chill.