In a medium saucepan over medium-high heat, warm the oil. Add onion, bell pepper and celery; cook, stirring, until vegetables begin to soften, 3 to 5 minutes. Add Creole seasoning, and cook, stirring, for 1 minute. Add rice, and cook, stirring, for 1 minute. Stir in 2 cups water, tomatoes and sausage. Bring to a boil. Reduce heat to low, cover, and cook 15 minutes, until rice is almost tender. Add shrimp, stir, and cook 5 to 7 minutes longer, until shrimp are cooked through and rice is tender.
