Spray bottom of a 13x9-inch disposable foil pan thoroughly with cooking spray. Pour half the jar of spaghetti sauce into pan and spread evenly.
In a small bowl, mix together cottage cheese, mozzarella, Italian seasoning, garlic salt and pepper.
Spoon cheese mixture into uncooked manicotti tubes and place tubes in the pan on top of the spaghetti sauce. Pour remaining spaghetti sauce over manicotti and spread evenly over the pan; sprinkle with cheese. Cover pan with plastic wrap and aluminum foil. Label and freeze.
When ready to cook, thaw completely in refrigerator overnight. Remove plastic wrap and foil, replacing loosely with foil.
Preheat oven to 375°F. Bake at least 45 minutes. Let stand 5 minutes before serving.