So, if you play with the brightness you will see the difference, but the new display is rather more neutral color-wise than the original iPhone which was offering a blue-rich display.
The display settings of the new iPhone 3G is very similar to the one of the first production batch of iPhone 1G dedicated to the US market. The blue-rich rendering appeared wit the iPhone 1G dedicated to the EU market. So it is NOT a display problem, rather a color calibration choice made by Apple.
