So I just discovered that my white iPhone 3GS has a piece missing from the bottom. I have no idea how or when it disappeared. I haven't dropped it and I treat this thing like a baby. I'm beginning to wonder if this was from a hairline crack that I never really noticed. Could a piece like this come off from a hairline crack expanding over time? I'm hoping to sell this iPhone so I can get the iPhone 4 in the next couple weeks. Obviously this will bring the price down so I'm hoping I can go in and get a replacement. Just wanted to see what ya'll thought first before making the trek. Thanks!