Melt butter in heavy large pot over medium-high heat. Add bell pepper, onion and garlic; sauté until onion is tender, about 5 minutes.
Add tomatoes with juices to pot; cook 2 minutes.
Combine 2 cups water and chipotle chilies in blender and puree. Mix puree and cream-style corn into vegetables in pot. Bring soup to boil. Reduce heat to medium and simmer 15 minutes, stirring occasionally.
Add frozen corn, cream and oregano; simmer 5 minutes. Garnish with cilantro, if desired.