Cook pasta in a large pot of boiling salted water as directed on package, until just tender. Drain, and set aside.
Heat olive oil in a small saucepan. Add green onions and cook, stirring occasionally, 2 or 3 minutes. Stir in garlic, and cook for 2 minutes. Add pasta, tomatoes, salt, and pepper. Cook over low heat to warm through. Stir in mozzarella and Parmesan cheese. Coarsely tear basil leaves in halves or thirds; add to pasta with olives, and serve immediately.