Members of CTIA include the four largest mobile carriers in the U.S.: AT&T, Verizon Wireless, Sprint Nextel and T-Mobile USA.

Until the alerts, it was too difficult for mobile customers to know if they were about to get hit with overage charges, Rosenworcel said. "How many people in this room know how many bits of data they have used so far this month?" she said. "Nobody should need to hire a lawyer to understand their wireless contract, and nobody should need to hire an accountant to explain their wireless bill."

The IDG News Service