There hasn't been an official announcement from any of the companies involved, but now that AT&T has officially taken over operation of Starbucks' in-store Wi-Fi hotspots, a raft of iPhone users are reporting that they can access Starbucks Wi-Fi access points free of charge. The system just requires users enter their phone number at a login screen in order to connect to the Starbucks access points.

Although free support for iPhone users in Starbucks locations wasn't foreseen, it's not very surprising: AT&T is offering free Wi-Fi to its residential broadband and business customers—including access through Starbucks locations. AT&T is also Apple's exclusive U.S. distributor of the iPhone, and Apple and Starbucks already have an agreement in place that lets iPhone and iPod Touch users tap into the Wi-Fi version of the iTunes store. Offering iPhone users Wi-Fi access via Starbucks locations is a simple way for AT&T to encourage customer loyalty—especially with 3G iPhones right around the corner.

Some reports indicate that users who can configure their Web browsers to pose as Mobile Safari can also access Starbucks' Wi-Fi access points for free, although, if true, the loophole will no doubt will be short-lived.