SBC Communications, 60% owner of Cingular Wireless, has agreed (WSJ Online subscription req.) to purchase AT&T for roughly $16 billion. SBC is no stranger to large mergers, it approved the $41 billion buyout of AT&T Wireless last year.

AT&T had previously announced plans to reuse its AT&T Wireless brand name to start a mobile virtual network operator (MVNO). It’s not known if the SBC buyout will affect this plan (having AT&T Wireless pop up again offering mobile phone service would be confusing for Cingular customers to say the least).

The deal is still subject to approval by AT&T’s shareholders and regulators. Analysts expect it to close in the first half of 2006.

BellSouth is the minority owner of Cingular Wireless.