Cook pasta according to package directions; drain, reserving 1/3 cup cooking liquid.
Meanwhile, heat olive oil in large skillet set over medium heat; cook onion and garlic for about 3 minutes or until tender.
Add shrimp to skillet; cook for 1 to 2 minutes or until just starting to turn pink.
Add pasta, tomatoes, cooking liquid and salt to skillet. Remove from heat and stir in basil. Divide among 4 plates. Sprinkle with pepper.