Rumors have been floating around pretty much ever since the white iPhone was delayed. There were both rumors about why it was delayed, and about when it would come out. Although we may never know the answer to why the white iPhone 4 was delayed for so long, we do know when it will come out. The answer: today.
Apple posted a picture of the white iPhone 4 on it's website yesterday, along with a caption saying that the white iPhone 4 will be available tomorrow. That tomorrow is now today.
The white iPhone 4 is available for purchase now, and many have already bought it. The ones who already have the device in their possession have started a buzz about the thickness of the white iPhone 4 compared to the black version.
The picture below shows the slight difference in the thickness of the white iPhone compared to the black Model.
Speculation is always possible as to what the reason for the thicker device is. However, I believe that this difference in thickness means next to nothing, and time should not be wasted guessing the reason for the thickness difference. One of the reasons that the white iPhone may be important, is that Apple wouldn't a new model of the same version phone if a newer version phone was just a few months away. This white iPhone launch seems to support the rumors that the iPhone 5 will not be coming out, as originally expected, in June 2011.
UPDATE: Apple responded to this claim by saying that, unlike what the picture above suggests, the white and black iPhone are actually the same size. Consumer Reports also did testing on this issue, and concluded that both models of the iPhone are the same thickness.