I got a copy of Coraline for my birthday, and it came with a few pairs of those red/green 3D glasses. I thought I'd have a go and making some of my own 3D photos. The idea is pretty simple, you take two photos of the subject, one from the position of your left eye, and one for your right eye. You then tint the left image green, the right one red, and merge them together (this can all be easily done in Photoshop or equivalent).
I think this one came out pretty well, the rotors on the top of this model helicopter really look like they're coming out towards you!