One of the biggest gripes about the iPhone 4, which has reportedly already sold 1.7 million units since its launch last Thursday, has been the antenna issues due to holding the phone on the bottom left side. While the initial answers from Apple were either buy a case or basically "don't hold it that way," Apple is now reportedly working on an iOS 4.0.1 update that may help alleviate the issue among others.
The biggest current debate on whether the signal issue is hardware or software related. iPhone 3GS owners have had problems with reception after upgrading to iOS 4, while the iPhone 3G was also plagued with reception issues upon launch. It seems that we may have some more answers when this update drops, which could be as soon as July 5th.