Sorry Ed, I've been a bit too busy to browse the forums otherwise I would have been able to answer you straight away, as I have one. In Australia they were marketed as the Polaroid 'Vision' camera and as Francois said, they store the taken image in a compartment at the back (with the last picture taken showing through a window, so in many way this was the analogue precursor to the LCD review screen on digital cameras)
If you find one for a reasonable price get it. I love mine and am always on the look out for more 500 film...
(sorry about the crappy example pic, it's late at night after a busy shift and the iMac's built in webcam is cruelly honest) :-)
[Sorry, image deleted during forum software upgrade. Please re-upload if so inclined.]