Last year's multibillion-dollar combinations of Verizon-MCI and AT&T-SBC resulted not only in the two biggest U.S. carriers but also in two monster billing-integration projects.

Neither megacarrier has made much headway in consolidating its billing systems, but they do have plans underway and are taking interim steps designed to boost customer service. Verizon at this point is much more forthcoming than AT&T about its efforts.

Customers are eagerly awaiting the integrated systems, which should result in more accurate and easier-to-understand bills. For now though, customers say they are just happy the mergers haven't messed up their bills.

“Right now billing systems are very siloed," says Burt Sky, director of carrier strategies and operations at Gartner. Consolidating them should benefit customers and the carriers themselves, which would be able to cut costs and speed service rollouts, he says.

Verizon is in the early stages of a two-and-a-half year plan to streamline 30 billing systems into four platforms, says Dave Landry, executive director of billing systems at Verizon Business Information Systems.

The challenge is great in part because billing systems mushroomed at MCI in the years before the merger as a result of the company's many acquisitions and its habit of creating a billing system for every new service deployed, Landry says.

Verizon eliminated one voice billing system soon after the companies merged and plans to consolidate dedicated data service billing platforms in the first quarter of 2007. “We are dealing with the largest of the billing systems upfront," Landry says. “There are some we won't convert. The products will atrophy and the systems will rust away over time."

Landry will not say which systems will rust away, not wanting to confuse customers. The four core billing systems are wholesale, a “boutique biller for ultra high-end customers," a local exchange carrier biller and a data biller that will cover everything else, he says.

But before Verizon gets down to four systems, it is making changes that should improve billing incrementally. These include standardizing on one data format for collecting bill information, integrating legacy MCI and Verizon customer portals, and implementing a new contract rate review platform that promises to improve accuracy.