Yesterday we learned that the new iPhone 4 has 512 MB of RAM on-board, but it may be packing some even more interesting internals.  Apple has sent a letter to the Federal Communications Commission asking that photos of the iPhone 4 be withheld for 45 days.  The reason? To hide "technical and design information that has not been publically disclosed."

It sounds like Apple has some surprises in store that they didn't tell us about at WWDC.  While no one is sure what is being hidden, I don't think that it's going to be some sort of huge surprise like a hidden CDMA radio or anything like that.  Apple is a very secretive company and they are pretty good about keeping products and features (with the exception of the iPhone 4) hidden from the public until they are ready to reveal them.  The iPhone 4 is launching next week, so it won't be long before all is revealed.  Apple's full letter to the FCC can be seen below.  What do you think Apple is trying to hide?

Via PatentlyApple