Before I begin, I would like to give credit where it is due. The main concepts of doing this I got from a Photoshop tutorial in madtuts.com (click for the original tutorial).
The first thing you will need to do is find a black and white photo. I decided to try using the most famous black and white photo I know of, “Migrant Mother” taken by Dorothea Lange in 1936. Open the image in The Gimp.