Kudos to AT&T. They've assembled a very useful FAQ page and cut several videos to lay out all the necessities of picking up an iPhone 3G. It includes topics like what you should have on hand if you're transferring a phone number from another carrier (bring you current wireless bill, they suggest, along with your old account PIN or passwords), the costs of various plans (they start at US$69, but expect to be jacked for text messaging), the unsubsidised price of an iPhone (US$399 for 8GB, US$499 for 16GB), and the unlocked, unsubsidised price of the iPhone (US$599 for 8GB, US$699 for16GB). So hit the links if ever wondered if hair will start growing in funny places once you buy your new iPhone (which it will). [iPhone FAQ and Helpful Videos]
For a shortcut to plan pricing, read on:
As for the subsidised iPhone pricing, AT&T has clarified that it's available for "new customers, current postpaid iPhone customers in good standing prior to July 11, and AT&T non-iPhone customers who are currently eligible for an upgrade discount" with a two-year agreement.