Only customers new to the mobile carrier, however, can complete the entire purchasing process online.

"Apple always wants to drive sales, and they're probably also clearing out inventory," said Ezra Gottheil, an analyst for Technology Business Research. Apple sold the first-generation iPhone online -- as well as at retail -- from June 2007 to when supplies were exhausted in May 2008 and let buyers activate the device using iTunes. But when the iPhone 3G debuted last July, it was sold only at Apple and AT&T retail outlets, where it was activated before the customer left the store. That move was prompted, most analysts agreed, by the , and the corresponding revenue loss to AT&T.

In September 2008, however, Apple let customers reserve an iPhone 3G online, then head to a store to pick it up and activate the phone. AT&T followed suit in December by selling iPhone 3Gs online, letting users activate it later -- and at home -- for the first time.

In lieu of online ordering of the iPhone during last year's holiday selling season, Apple only had iPhone gift cards to offer.

The warns consumers that only customers new to AT&T can complete the process entirely online, and tells people with existing AT&T accounts that they will still need to pick up the device at an Apple store.