AT&T has a statement on their site where they (kind of) respond to the allegations that they helped the NSA in spying on American citizens.
The news media have carried reports alleging that AT&T is participating in an unlawful NSA terrorist surveillance program. Unfortunately, the law does not permit AT&T to respond to those allegations.
The U.S. Department of Justice has stated that AT&T may neither confirm nor deny AT&T’s participation in the alleged NSA program because doing so would cause “exceptionally grave harm to national security” and would violate both civil and criminal statutes. Under these circumstances, AT&T is not able to respond to such allegations.
So basically, they have a policy protecting the privacy of the government agencies, not yours. I guess I know which carrier not to go with when the telecommunications market gets opened around here.