I'm actually doing that right now. I just got a 8900, so I put my prepaid t-mo sim from my backup phone into my old 8320. Now since I can't use data on prepaid, I just pop in my sim from my 8900 when I need a new app or something downloaded to the 8320.
Simply I mean you're old device will still have all service books and settings so everything should keep on working when you swap back and forth.
So in short yes, though I'm sure if you plan on doing it often, having to continuously swap sims and boot each device will probably get on your nerves.
Of course if you are using your pearl just for the camera, your camera will of course still work even without the sim card installed.