Preheat oven to 375 degrees. In mixing bowl, combine softened cream cheese and 1/3 cup sugar, mixing until well blended. Blend in one egg.
In saucepan, combine water, margarine, and chocolate; bring to boil. Remove from heat. Add combined remaining sugar and flour; mix well. Blend in remaining eggs, sour cream, baking soda, and salt.
Pour into greased and floured 15 1/2 x 10 1/2 inch jelly roll pan. Spoon cream cheese mixture over chocolate batter. Cut through batter with knife several times for marble effect; sprinkle with chocolate chips.
Bake for 25-30 minutes or until toothpick inserted in center comes out clean. Cool; cut into squares.