That's good news for those customers, but AT&T;'s critics say it should stop withholding the feature from the last group still being excluded: those with grandfathered unlimited data plans.
FaceTime is Apple's proprietary video calling feature that launched in 2010 with the iPhone 4. Initially, the feature could only make video calls over Wi-Fi, but Apple added cellular call functionality last September with the launch of iOS 6, the latest version of its mobile operating system.
Both Verizon and Sprint, the two other major U.S. carriers of the iPhone, allowed cellular FaceTime calls for all their Apple users from the start.
AT&T;, however, made the feature exclusive to iPhone owners on their Mobile Share data plan. The company later revised its policy and said iPhone 5 users with tiered data plans could also make cellular FaceTime calls.
That still left out other iPhone users, such as those with iPhone 4 and iPhone 4S, who have the tiered data plans as well as those with unlimited plans. This week, AT&T; revised its policy again and said all iPhone users with the tiered data plan would be able to make the FaceTime calls.
But the policy change still left out those with the unlimited plan.
Free Press, an organization that's been criticizing AT&T;'s decision to block some users from the feature, said AT&T; must make cellular FaceTime available to all its iPhone users. If it doesn't, the public interest group Free Press said it would file a complaint with the Federal Communications Commission -- although the organization has been making that threat for months now.
"AT&T;'s announcement is another step in the right direction," Free Press said in a statement. "Yet as we've made clear all along, the company has no right to block the application in the first place. Until AT&T; makes FaceTime available to all of its customers, it is still in violation of the law and the broader principles of Net neutrality."