With the iPhone 2009 launch looming large, Apple wants to get rid of the existing iPhone stocks real fast and to do so it has allowed unrestricted purchases of the iPhone from Apple retail stores. So a single buyer can now purchase more than one iPhone at the full price without entering into any contract.
This is significant as previously, buyers could purchase an iPhone in US only from AT&T, but now they can directly purchase it from the nearest Apple retail store at the full price (and not at the subsidised rates offered by AT&T) and get it activated from iTunes directly. The full cost of the 8GB iPhone is $599, whereas the 16 GB model costs $699.
The iPhone was heavily subsidised by the Service providers like AT&T that sold the 8GB and 16GB models for $199 and $299 respectively and recovered the subsidised costs from the users by making them enter into a minimum 2-year service agreement. But now it has decided to sell only one iPhone per user and hence it has become imperative for Apple to start selling the iPhone through its retail stores in order to quickly empty the existing iPhone stocks before the new iPhone 2009 is launched.