AT&T hopes to simplify life for itself and for Apple iPhone 3G buyers this holiday season. The wireless carrier said customers can now go online to perform a pre-qualifying credit check and see if existing phone numbers can be ported to AT&T’s network before visiting a retail store to complete the purchase.

The new online features are similar to what Apple already offers – for example, customers can go online to select a service plan if they intend to visit an Apple retail store. An AT&T spokesman said the announcement is intended to ease store lines ahead of the winter holidays.

The company also wants to avoid a repeat of the activation glitches experienced when many customers signed up during the phone’s initial launch this summer.

Unlike last year, the iPhone now has competition such as the Sprint Instinct from Samsung, Verizon Storm from Research In Motion and a variety of unlocked Windows Mobile phones. However, market leader Nokia’s 5800 XpressMusic phone will not be widely available until early next year.

AT&T is not ready to disclose its other plans for ramping up holiday sales, officials said.