This is a double post but I am too lazy to type again. Martin Fields got some trusty screen protectors, please read below.
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I saw the testings and believed the screen is actually pretty unscratchable. However, I'd rather put a screen protector on so my oily face won't make the pretty glass dirty. It's a 600 bucks phone, you can buy a PS3 or a full set of xbox360 + HDDVD player with it. I don't have the money to buy another, so I'd prefer to take good care of it. I know they sell PowerSupport screen protectors in the apple store, I haven't tried those, but I am recommending the Martin Fields screen protectors. I have it on my old Treo650 and my E62 and they are excellent. It's like putting on a new screen on those phones. It's crystal clear and make the screen look as bright as if you don't have anything on it. It's removable and washable too. I already ordered 2, one for me and another for my brother. Link below if anyone's interested.
<Martin Fields iPhone screen protector Link>