Yep, mine rattles, too. Black 64GB AT&T. I noticed this a couple days after I bought it (11/4). I noticed it when I'd set it down on my desk, or what ever. Then started to try to localize the rattle by tapping around on the phone. Its definitely the camera. I was also able to change to tone of the rattle (almost eliminate it) by zooming in and turning on auto focus lock. Seems when the lens/lenses is/are relaxed they rattle on each other. Not so much when zoomed/compressed...
So I called Apple, and was told over the phone that "this isn't right" and "your phone camera should not rattle" (Duh!). They made me an appointment to see a "genius" at my local store to get it swapped out. The genius had a different customer service plan.... She basically didn't listen to anything I said, and proceeded to take it in back, undo the back cover, and remove & replace a couple screws (convinced that something else was loose). She comes back and says they all do it. Her own phone did it, and so did the display phones (the 4 didn't do it quite as much). She was not about to give me another phone. But why bother if the replacement will have the same issue, right? Being that they are so hard to come by right now I doubt I could have even been given a new one right then and there anyway's...
Sure, they may all do it....BECAUSE MAYBE THE ENTIRE BATCH OF CAMERAS ARE CRAPPY!(?) My old 3GS' camera rattles slightly, but no where near as bootleg-component-sounding as the 4S. I think that sure, this is the nature of this particular camera, but it still seems to me that it's a poor design. If this is an engineering compromise then I think Apple should state these characterstics in their product page for their phones. At least give us a heads up like: "the camera is rad, but...." This just really ruins a little bit of the otherwise amazing engineering asthetic of the overall device, IMO.