Two questions

Hi I have an iphone 3g and I have two questions:

1) I’d like to use to GPS funtion in the iphone, I did when I first purchased it but in august of 2009 I was given an extra charge, and I assumed this was from GPS (I have an unlimited data plan so I was confused about it). Is the GPS funtion free, or does ATT charge for it

2) My iphone has 6 stuck pixels. Some of them go away but they always come back, and it’s rather annoying. Does ATT cover this under warranty?