It's very simple though, you can do it yourselves without facing any problem. What you need to have a magazine with any part of face and face of your own and probably another person who'll take a picture of you. Let him (or her) direct you on how to make the best pose in order to create the perfect illusion. See how these people did it. This is little bit confusing even the photographer must be in a perfect position to capture a good image to create an illusion
So what are you thinking come pick up your camera and start picking up the pictures to create an illusions and don't forgot to send me if you want me to publish on my blog