If you ran out and purchased an iPhone 4S recently, you might want to take a hard look at your screen. Some iPhone 4S users are complaining that there is a yellowish discoloration of the screen on their handsets. Some are going so far as to claim the discoloration is on the black version of the 4S only. If you have followed iPhone woes for long, you will know that the iPhone 4 had a problem with glue that hadn't cured on some devices leaving a yellow discoloration in the past.
With the iPhone 4 smartphones that were affected by the yellow discoloration, some eventually cleared as the glue cured, Apple also replaced some devices that were yellowed. There were also issues with yellowing on the screen back in the iPhone 3GS days as well. If your iPhone 4S is affected there are a couple things you could do.
You could just wait a while and see if the yellow discoloration goes away. You could also take the phone into a local Apple store and have it looked at. If you have an iPhone 4S that is yellowed, be sure and let us know in the comments and a video would be nice too. One person with an affected 4S described the issue:
my 4S screen is less contrasty, and the whites are more yellow (beyond 'warm') compared to my iPhone 4 screen. The colors are less vibrant, and some are pretty washed out. I've also noticed that the screen is more directional than the 4 screen, and in some viewing angles it's more yellow, and in others it's more contrasty. I'm really hoping this is a glue issue, which could improve. I don't think I'll be able to get used to this.