I recently watched Waste Land. Fantastic documentary about New York Brazilian artist/photographer Vik Muniz's photo project in a huge garbage dump outside Rio de Janeiro.
Muniz takes portrait photos, transforms them into object collage, and then photographs the result- that's a simplistic explanation that doesn't do any justice to his work. Very worthwhile viewing, amazing project. Also available on iTunes.
Along similar lines, I watched this TED lecture presentation by Paris paste street artist/photographer, Jr.
He also takes portrait photos, but blows them up huge and pastes them in street art settings. Some of his projects go to international scale with social political messages, and complement Vik Muniz with similar locations.
This is a 25 min presentation. If you aren't hooked at first, stay with it, the second half is a very worthwhile payoff (although I enjoyed the entire presentation). It sounds like there will be a feature film based on the content here.
JR's TED Prize wish: Use art to turn the world inside out | Video on TED.com