Apple's newly introduced 16GB iPhone is causing some confusion with those who wish to upgrade, regarding whether or not the upgrade would require re-signing a contract with AT&T. According to Scott Kleinberg of iPhone, Therefore I Blog, purchasing a new 16GB iPhone and using it as an upgrade to an existing plan does not extend the two-year contract. Activation requires the user to acknowledge the contract, but the effective start date remains when the plan was initially introduced.
This information came to Kleinberg from an AT&T spokesperson that he trusts, and has been corroborated by a few users in other forums.
The spokesperson wrote Kleinberg with the following information: "iPhone customers who want to upgrade from their current model to the 16 GB iPhone can do so without extending their contracts. They can also keep the same phone number. We apologize if anyone has been told differently. Our sales teams have this information and we're excited by the interest and our ability to provide our customers with even more choices for their wireless needs."