UPDATE 2: Daring Fireball checked with source at Apple's iPhone Engineering who confirmed that:
there were no changes regarding display color temperature between 5A345 and 5A347, and that there’s no practical reason why someone with an iPhone with 5A345 installed should go through a complete system restoration just to get 5A347.
And that, while there did appear to be differences in "yellowness" from iPhone 3G to iPhone 3G, it was not due to firmware (perhaps components?).
UPDATE: If your screen is really too yellow, like Simpson's yellow, some users are posting that by hooking your iPhone 3G up to iTunes and doing a restore, the shipped firmware buld (5A345) gets replaced with the newer firmware build (5A347), which is less yellow. (Thanks Jack for the tip!) I can't recommend it since I haven't done it personally, but it's always an option. Also, Daring Fireball is reporting that more recent iPhone 2G models also have the warmer yellow screens. He thinks this may indicate a hardware change, but I'm not sure if he checked all the firmware details yet?
The interwebs are literally a Twitter about the new iPhone 3G and it's brighter, yet strangely yellower screen. While some people can't seem to see a difference, or can only notice the difference when compared side-by-side with an original iPhone 2G's darker, more blue-tinted screen, for others its annoyingly obvious.
Personally, I'm in the second camp while Brian seems to be gravitating towards the latter, especially considering Apple in their usually hyper-controlling manner, has failed to provide a way for individuals to control their own screen settings and change the hue, brightness, and other display aspects themselves.
Turns out it's not an accident either. Engadget tracked down Bob Borchers, senior director of product marketing for the iPhone, who shed some light on Apple's thinking:
According to Bob (and Apple), the screen's color temperature has been purposely altered on the new iPhone to produce warmer, more natural tones, sharper images, and deeper blacks. The company says that 1st gen iPhone screens appeared colder and less defined, and they made some adjustments for the new models. In our opinion, what he says is right on -- the screens do look better on the iPhone 3G versus the older variety.
Brian's heading back to the Apple store, since he's convinced his yellow is far too yellow. Mine's okay so far. How's yours?