Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente, drain.
Meanwhile, in a large bowl, combine ricotta cheese, 4 ounces mozzarella cheese, Monterey Jack cheese, sour cream, bread crumbs, parsley and salt and pepper to taste; mix well.
In a 9 x 13 inch baking dish, spray dish with non-stick cooking spray and cover bottom of dish with a thin film of spaghetti sauce.
Fill each manicotti with cheese mixture and place in dish; cover with remaining sauce. Sprinkle remaining mozzarella cheese on top of sauce.
Bake in preheated oven uncovered for 40 minutes; serve.
