How to access FaceTime on iPhone 4s?

I have an iPhone 4S. So I should have FaceTime

But I don't think I do. When I look under settings, I don't have it. When I click contacts and look for FaceTime under them, I don't have it either. How can i access it?

You need to have an apple ID and add contacts with people who have it and have enabled FaceTime as well. You should have iOS 5.1.1