A loophole means unlimited data for AT&T iPhone

Verizon Wireless will start offering the iPhone on Feb. 10 with a draw that AT&T no longer offers to new subscribers: a plan with unlimited data usage. But some AT&T iPhone users on limited plans won't need to move to Verizon for all-you-can-eat data.

In an unadvertised loophole, AT&T has allowed subscribers who have had an unlimited data plan in the past to switch back. That includes anyone who had an iPhone before June, when the limited plans took effect. The company has allowed iPhone and smart-phone users with unlimited-data plans to keep them when upgrading directly to a new phone. It's the option to return to an unlimited plan after going limited that's been secret.