While it is under warranty you are missing out on a big piece of the legit American iPhone warranty, Apple will run the phone information and see that you don't have it activated with AT&T, if you relocked it and then activated it with AT&T they'd just go ahead and take a look at it, but I honestly can't see them replacing it because it has a small bit of dust under the screen but they won't even take a look at it if it isn't or hasn't been activated on AT&T.
Ic. Well, I did a search on Google, and someone got it replaced.
I just called them and asked if I could put the iPhone on an On the Go Sim Card from AT&T, and the guy said that's not a problem... so if I just go down to Buffalo and get me one of these sim cards, then I could always pop into the Apple store and have them take a look it.
Even if they don't replace it, I'm sure they can take it apart and fix it for me. It does bother me, cause I KNOW it's there.
In October when I had an iPod touch (which I sold to get the iPhone), I had a similar problem up near the battery icon. I sent that into Apple and they sent me a new (or refurb, I dont know, but it was in perfect condition.) iPod touch.