I went through the polaroid conversion process years ago when i did a run of Zhora pics.
Here's the deal:
The best thing to do is buy a pack of polaroid film. Crack the case open, and carefully take out all the pics.
Take a pic and flip it onto it's face, so the picture part is face down.
use an x-acto blade to CAREFULLY peel up the lip of casing along the top of the pic. It's sealed at the corners. If you tear it, no big deal, as it will be on the back. Once you get the lip separated, just fold it over towards the front.
Print your picture out at the appropriate size. Be sure to include the white border so that it sits properly within the polaroid frame. Might take a couple of tests to get it right. Be sure to print the pic slightly bigger so that it's framed properly inside the pic.
Slide in the picture. BUT be careful. The bottom of the polaroid picture has a well that is filled with the developing solution. When the pic pops out of the camera, this solution is squeezed from the well into the body of the frame. DO NOT SQUEEZE it out. It's REALLY messy, and will ruin the photo that you just put in.
Once you get the picture inside, use some two sided tape, contact cement, or some of that super thin mounting adhesive to seal up the flap.
I would then recommend putting it into a frame or shadow box. Handling of the picture will eventually result in someone squeezing the well of fluid into the casing and ruining your picture.
Hope that helps!