Marketing materials for camera-equipped phones tend to focus on megapixels, flash, and video capability. As anyone with a little experience with digital photography knows, these are not, actually, the most important things. A little research has shown that the real useful information (sensor size, max aperture, even focal length) is difficult to find, and there doesn't seem to be an all-in-one place to find the answer.
Hopefully we can solve that with a community wiki. I've moved to here some of the information I've collected in trying to answer my earlier question about what Android phone is best for photography. Please contribute what you know, preferably with sources.