Although it was discovered as a "feature" a week ago, it's not official until AT&T says it is. And finally on Thursday the ability of iPhone users to use AT&T hotspots at their 17,000 locations was added to the details of the iPhone plan on AT&T website. Then they removed it again.
AT&T's iPhone website (under 'Plans' tab) has been updated to reveal that each iPhone plan now includes access to their "more than 17,000 Wi-Fi hotspots, including Starbucks all for use in the U.S."
It was first revealed last week that AT&T had quietly begun offering iPhone users access to their Wi-Fi hotspots for free (including Starbucks and Barnes & Noble). No official announcement had been made, however, and the service was abruptly turned off a few days later.
Update: AT&T has changed the text on their site to remove the Wi-fi reference.
So why can't they make up their minds? Possibly it's because of the user agent hole that allows users who change the user agent on their browser to user AT&T hotspots without a real iPhone. Or maybe they're just indecisive.