Apple Thoughts: AT&T WiFi Made Easy With 3.0

"It looks like AT&T might be using the 802.21 protocol to relax the pressure put on their 3G network by the iPhone. The new iPhone 3.0 OS software contains the ability for iPhones to autoswitch from 3G to Wifi when an AT&T Wifi network is in range, without user intervention."

Once you have visited an AT&T hotspot, the next time you won't have to go through the normal two-step sign on process. With the iPhone 3.0, after you have visited the network at any of the 20,000 AT&T hotspots, it will "seamlessly" switch you from cellular to the Wi-Fi the next time you stop by the same location. It started yesterday for anyone that has the 3.0 software installed. AT&T has posted a news release outlining all the details.