Heat olive oil in a large, deep skillet over medium-high heat; add onion and garlic, and sauté 3 to 5 minutes or until tender. Add wine and tomatoes, and bring to a boil. Add mussels; cover and cook 3 to 5 minutes or until mussels open. Discard any unopened mussels.
Remove mussels with a slotted spoon, and place in serving bowls. Add basil, lemon rind, and pepper to liquid in pan; add butter, and swirl in pan until melted. Spoon sauce over mussels. Serve immediately with warm, crusty bread.