AT&T is now the worst-rated cell-phone service carrier according to a new survey of “Consumer Reports” readers. ANd U.S. Cellular, a regional carrier that provides service in 26 states, beat out the long-standing top provider Verizon Wireless with outstanding marks for value, voice service and customer support. 

The full article also features carrier ratings in 23 metropolitan markets and is in the January 2011 issue of “Consumer Reports” and at . In this year’s version of an annual “Consumer Reports” survey on cell-phone carriers, more than 58,000 subscribers weighed in about their service and customer support experiences with contract and no-contract providers. 

AT&T was the only carrier whose scores for overall satisfaction dropped significantly since last year. Verizon Wireless remains among the better performers, but Sprint has pulled even with the carrier in overall satisfaction. The carrier actually even scored better than Verizon in some aspects of customer service, a remarkable turnaround from past years when that was a weak point for the company, notes “Consumer Reports.” T-Mobile was only slightly behind those two carriers in overall satisfaction.

More than half of the AT&T customers surveyed owned an iPhone. “Consumer Reports” data, reflecting all versions of the phone, found that iPhone owners were much less satisfied with their carrier and rated data service (web and e-mail) lower than owners of smart phones on other carriers that, like the iPhone, have a host of apps to encourage heavy data use.

“Our survey suggests that an iPhone from Verizon Wireless, which is rumored, could indeed be good news for iPhone fans,” says Paul Reynolds, electronics editor for “Consumer Reports.”