Looks like the iPhone 4 might have some additional problems aside from display and cellular connectivity issues that have been detailed before this. Many users are reporting, over in the Apple forums, that the proximity sensor doesn’t seem to be functioning properly. The proximity sensor would normally turn the display off when the phone is placed close to your face, so that your cheek wouldn’t accidentally hit the any of the buttons on the display, such as muting, or ending the call. The problems seem to vary, but some users do report that the screen does indeed go blank, but you’re still able to accidentally initiate a FaceTime call or other features by pressing the correct place on the screen. Doesn’t sound too encouraging, does it? Have you encountered such issues with your iPhone 4, and have you found a solution to it?