After numerous fits and starts, AT&T (NYSE: T) is finally going official with its plan to open up its thousands of Wi-Fi hotspots for free to iPhone users. The carrier has even informed some iPhone customers of the change via text message, TUAW reports. But since we know people who haven’t received the text, hopefully this is something that will be rolling out over time. The service has been working on and off since April and was first announced in February. Compare that to T-Mobile USA, which opened up its network of Wi-Fi hotspots immediately when the carrier launched the G1 last week.