Food.com offers an oatmeal crumb topping that works well on pies. MarthaStewart.com also offers a crumb topping recipe that goes on pies, frozen yogurt, fresh fruit and ice cream.
The recipe from Food.com requires 1/2 cup butter, 1 cup brown sugar, 3/4 cup flour and 3/4 cup non-instant oatmeal. Add cinnamon and salt to taste. Combine all of the ingredients except the butter together, and then add the butter with a pastry blender until the mixture looks like bread crumbs. The recipe from MarthaStewart.com requires the same ingredients without the oatmeal. When baking with a pie, simply add the crumbs on top of the fruit without adding an additional top crust.