Melt butter in medium saucepan over medium heat. Add onions and saute for 2 to 3 minutes until soft. Add corn and saute for 10 to 12 minutes. Stir in garlic, jalapenos, cheese, and cream. Cook for 5 minutes or until thickened. Season with salt and pepper.
Pour into fondue or warming dish. Sprinkle with tomatoes and cilantro.