Adding shadows, brightening some parts of the picture, and giving the pics a more shadowed and spooky look. They look more like paintings. I'm not going to give away my secrets but I've been messing around with Photoshop CS4 (got it yesterday) and developing this technique.
Here's two others that I did (MkII love):
http://i3.photobucket.com/albums/y59/14biggy/IMG_3621-after_alex.jpg
http://i3.photobucket.com/albums/y59/14biggy/MKIIHDR1.jpg