Bring a large pot of lightly salted water to a boil over medium heat, and cook the pasta for about 8 minutes, until tender. Drain, and return to pot over low heat.
Lightly mix in the ham, peas, and milk, and sprinkle in the pepper and garlic powder. Stir in the Cheddar and mozzarella cheeses, and cook about 5 minutes, until the cheese melts and the mixture is bubbling.
