3-Sweep: Extracting Editable Objects from a Single Photo [video]
Also awesome is that it handles the background replacement so well. This could also be used to just remove an ugly lamp post, telephone pole, etc from an otherwise good photo. (assuming you can remove objects and resave the image)<p>Edit: I am aware that Photoshop has some of this available. I've not played with it so I don't know how they compare.