The other day, after upgrading an iPhone to OS 3.0, I noticed something peculiar yet welcome: while waiting in line at a Starbucks, my iPhone automatically logged into the café chain’s AT&T-supported Wi-Fi network. I didn't have to do anything. No entering my cell phone number, getting a text message, and clicking the link like I had to do before. The same proved true at another AT&T hot spot in McDonalds.

Turns out I'm not the only one who's having an easier time connecting to AT&T hot spots thanks to latest iPhone firmware, which removes the cumbersome two-step authentication process of previous iPhone operating systems. This past quarter, during which Apple released the major iPhone platform upgrade, AT&T saw 15 million users connecting to its 20,000 public hot spots, a nothing-to-sneeze-at 41 percent increase from the previous quarter.

According to AT&T, the new auto-connect feature is established once a customer connects their iPhone to an AT&T Wi-Fi Hot Spot the first time. It is something the carrier was keen on offering its customers.

After all, by allowing folks to connect to the Internet via Wi-Fi takes a lot of pressure off of its 3G network. About 42 percent of iPhone wireless usage is over Wi-Fi.

"Auto-authentication makes it even easier for iPhone customers to stay connected on the nation's fastest 3G network and the nation's largest Wi-Fi network," said AT&T Mobility president and CEO Ralph de la Vega in a statement. "With access to our U.S. hotspots, customers are receiving a great value, with a fast, reliable broadband connection virtually anywhere, through 3G or Wi-Fi."

In addition to iPhoners, AT&T allows many of other BlackBerry, Windows Mobile, Symbian, etc. smartphone and laptop users to access Wi-Fi for free, as long as they sign up for a qualifying wireless plan.

49 percent of those who connected to AT&T's hot spots lat quarter did so over a smartphone. "Our Wi-Fi network is a competitive differentiator for AT&T and a major value for our customers," said AT&T Mobility chief marketing officer David Christopher, in a statement. "We include unlimited Wi-Fi access with the majority of our broadband and smartphone plans, and our customers are clearly taking advantage of it. It’s another reason that twice as many smartphone customers choose AT&T than any other carrier."

In all, AT&T says it as surpassed 25.6 million Wi-Fi connections this year, about 20 million more than the previous year.

In addition to Starbucks and McDonalds, AT&T delivers Wi-Fi service through many other restaurants as well as airports, hotels, universities, convention centers, sports centers, and bookstores, including Barnes & Nobel locations.