Preheat oven to 375°.
Combine first 6 ingredients in a 2-quart casserole coated with cooking spray, and toss well. Combine the flour, brown sugar, and salt in a small bowl; cut in margarine with a pastry blender or 2 knives until the mixture resembles coarse meal. Stir in pine nuts. Sprinkle flour mixture evenly over peach mixture. Bake at 375° for 30 minutes or until lightly browned and bubbly.