Andrew Odewahn of O'Reilly Answers posts a HowTo on creating 3D(ish) images through simple processing. Odewahn employs the practice of stereoscopy (a technique for creating the illusion of depth in a 2D image):
"In wiggle stereoscopy, the 2 images are aligned so that the 'subject' overlaps, and then the right and left images are alternated quickly. Past a certain frequency, the brain interprets the alternations as parallax motion, which creates the illusion of depth. (It's important to note that this is not really a 3D image, but rather a visual trick. True 3D is more complex.)
The first step is to take 2 photographs; fairly simple objects work best. Take the first picture of the object and then (and this is the important part!) slide the camera to the other eye and take the same picture, but at an offset. This is the tricky part -- you don't want to change the angle of the camera or move your position in any way. You simply want to slide the camera from one eye to the other, keeping the lens in the same plane. With practice, you'll get the hang of it."
Here's a very rough demonstration (click through to see better examples of the animated gifs):