By Sam Oliver

Published: 11:00 AM EST

AT&T saw nearly 15 million users connect to its Wi-Fi network last quarter -- a 41 percent increase over the previous quarter -- thanks, in part, to the release of iPhone 3.0, which allowed auto-authentication on the wireless carrier's 20,000 hotspots.

For iPhone users alone, the number of Wi-Fi connections tripled in June following the new software release, an AT&T spokesperson told AppleInsider. In all, 49 percent of users connected who connected to the network did so via smartphones.

AT&T has handled 25.6 million Wi-Fi connections in 2009. That blows away the total number of customers in 2008, when the service was used by 20 million.

"Our Wi-Fi network is a competitive differentiator for AT&T and a major value for our customers," said David Christopher, chief marketing officer, AT&T Mobility and Consumer Markets. "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 June, coinciding with the release of iPhone 3.0, free auto-authentication for iPhones on AT&T Wi-Fi hotspots was enabled. This after months of delays and numerous premature announcements for the service.

During the holdup, AT&T has made expansions to its Wi-Fi network, and the company plans to continue its growth. Since the start of 2009, the company's Wi-Fi network authentication capacity has quadrupled, in anticipation of the influx of iPhone users. Since July of last year, the number of Wi-Fi hotspots has expanded from 17,000 to 20,000.

iPhone owners can find AT&T Wi-Fi hotspots in cafés, bookstores, airports, hotels, and universities, or at a nearby Starbucks.

"Our customers want both speed and mobility," said Angie Wiskocil, senior vice president, AT&T Wi-Fi Services. "They love the convenience that AT&T Wi-Fi offers, and we continue to enhance our Wi-Fi network, expand our portfolio of Wi-Fi enabled devices and extend our hotspot footprint to offer the best customer experience."