Cupertino (CA) - One of the little known mysterious features of the new iPhone 3G are two clearly visible screws positioned at the bottom of the handset. Two screws may not mean much, but they are fuelling a discussion why these two screws are necessary when virtually all of Apple’s gadgets have no visible screws. The leading opinion appears to be that Apple may be offering iPhone owners a way to replace the battery by themselves.

The fixed battery in today’s iPhone is one of the big annoyances of the device. Not only is its capacity limited, it also loses battery time relatively quickly over time, forcing iPhone owners to have the battery replaced by Apple for $86, which will cause all data on the phone to be erased.

Apple’s iPhone guided tour released ahead of the iPhone 3G launch details now provides some clues that Apple may have reacted to complaints and offer users to replace the battery without having Apple to exchange the device. The guided tour focuses mainly on the AppStore and covers new features of the iPhone 2.0 software update. However, eagle-eyed users spotted very unusual "feature" revealed at the 1:52 mark of the longer video: The bottom of the handset shows the speaker and microphone as well as two visible screws.

Apple’s dislike of any visible screws has become almost legendary, so it is no surprise the rumour mill is spinning at full speed over two tiny screws. Considering Apple’s product strategy, visible screws are a remarkable design change and it is believed that there may be a very good reason behind this "feature".

Some are speculating that removing these screws will allow the handset to open up like a clam for easy access to the battery. Your guess is as good as ours on this one, but this theory seems a bit stretched to us. There are other, more innovative ways to open up the shell of a cell phone and screws just do not fit to the iPhone. That, however, leaves the question why there are screws. We will wait for the first tear-down stories likely to surface a few hours after the iPhone’s release to find out.