I got the iPhone 3GS on Saturday. This is my third iPhone so I am very familiar with the device. Since I got the 3GS every now and again, the screen becomes unresponsive to touch. Like, I might slide the screen over one and the screen won't do anything. The only thing that will make it work again is if I lock and unlock, which works every time. I didn't have 3.0 till I got the 3GS so I wasn't sure if this was a software issue with 3.0 or the hardware on my new phone. My concern is that I cannot repeat this issue on command so even if I take it to the Apple store there is no way I could prove to them the issue.