AT&T Inc., the country's second-largest wireless carrier, announced Monday that it's setting up a "1-800" service for wireless data. Websites that pay for the service will be toll-free for AT&T's wireless customers, meaning the traffic won't count against a surfer's monthly allotment of data.

It's the first major cellphone company to create a comprehensive service for sponsored wireless access in the U.S. The service is likely to face considerable opposition from public-interest groups that fear it could discourage consumers from exploring new sites that can't afford to pay carriers for traffic.

AT&T is trying to forestall critics by announcing that one of the first customers for the service is a startup: Aquto, which has an app that rewards users with extra data if they watch ads or download specific apps.