The old ones come apart pretty easily.. just unscrew the bottom (the screws are underneath the rubber feet) and the whole top comes right off. I did it a while back to get in there and clean the lens (which is one advantage the newer one has.. the flip-top loader, you can access the lens anytime you like).
As for the newer one.. I don't have one, so I've no clue how to get it apart. It may be similar to the old one, though.. look around for "hidden" screws on the bottom.
If that doesn't work, hit up Google, or a video game forum somewhere.. I'm sure someone somewhere has taken the thing apart and could tell you how to do it.