Just looking at the pictures taken by iPhones.ru tell the story. The picture on the left was taken by the newly updated firmware for the iPhone (v. 3.0) and on the right is the older version(v. 2.2.1, which should be on all devices now.). Just comparing the two you can tell the v. 3.0 beats out the v. 2.2.1 on quality. Now there could be the argument that this will happen when you take two or three quick snapshots. . . this was the product of 30, all looking the same as the pictures show above.
Now, if you think long and hard at this, you will say to yourself,"How could this be, I don't get a better lens with a firmware update!". You are correct, a lens would consist of better hardware, which will not be seen with the likes of Apple making it (meaning, they will just make you purchase a new device). But when the lens feeds the information in to the device the firmware will need to delegate what to take and what not to take, making the quality better with a better firmware.
Those of you reading this have the iPhone 3.0 please feel free to leave a comment for us to judge.