Preheat oven to 350 degrees. Spray a 2 quart casserole dish with Pam. Arrange peach slices in bottom of dish. In a small bowl, combine granulated sugar and orange juice. Pour over peaches; set aside.
In bowl, combine margerine, brown sugar, corn flake crumbs, flour, and cinnamon. Sprinkle over peach mixture. Bake for about 25 minutes, or until golden and bubbly.