scott, unfortunately, that's a fake photoshop tilt-shift effect. you can tell by the line of the gradient. and a couple other things that are hard to explain: the height of objects and where they fall on the ground plane relative to where they're sharp focus. blah.
the main reason tilt-shifts are used: to keep vertical lines vertical instead of slanted because of a wide-angle lens:
http://www.flickr.com/photos/mc9/3094965982/