This is a pretty interesting NY Times article on a study done on identical twins and how differently they aged, depending on environmental factors. There is a slide show where you can see sets of twins and see how things like sun exposure and smoking caused them to "age" differently as far as wrinkles are concerned.
Here's the link: http://well.blogs.nytimes.com/2009/02/05/twin-studies-explain-wrinkles-of-aging/#more-855