Anybody has idea why the screen on 3g is yellowish comparing to 2g iphone

According to apple, its normal. Quick search on google will give you an answer.

According to a news report.

Apple’s Senior Director of Product Marketing, Bob Borchers, has since contacted Engadget to state that the screen on the new iPhone 3G is more yellow and that it is deliberate.

Apparently the change is due to shifting the hue of blue-biased LCD of the original iPhone in order to produce more accurate colors most of the time with deeper blacks, and generally crisper images.

For iPhone 3G users that don’t like the change, it is possible to alter the yellow tint a little by cranking the brightness up a bit, so long as you don’t mind looking at retina scorchingly bright images.