i would say take snapshots of everything of what you want and take those into CS3… Now say, you have a still frame of a man. Take the lasso tool and lasso his head, arms, legs and everything else and each time you do that, create a new layer and paste (on the new layer) what you’ve just lassoed.
Then when that is finished, load the photoshop file into after effects and when a dialogue box opens click “select layer” and choose, body. Then repeat the process until you have all the layers separated and then just play around with the arms and legs and head and body with the position keyframes and you should have.
I’ve only seen Mythbusters once, during shark week… i don’t exactly remember the effect but i have some idea of what it looks like… kinda like the beer commerical where the two guys are like “Brilliant!”?
hope this helps!