AT&T has announced its intention to acquire the last remaining pieces of Alltel that were left behind after Verizon Wireless acquired most of the company in 2008.

AT&T will pay $780 million in cash to Atlantic Tele-Network, Inc., and add 585,000 Alltel customers to the AT&T family in six states: Idaho, Ohio, Illinois, Georgia, and North and South Carolina.

Prior to the Verizon sale, Alltel used to operate in 34 states, targeting small and medium sized cities. The company was well-regarded for its innovative plans and features that distinguished it from its larger rivals. Among them: Alltel Family Finder helped parents keep track of children, My Circle allowed customers to make and receive unlimited free calls to and from any number in a calling circle, including landlines, and U Prepaid offered customers the chance to make unlimited calls to one number of their choice.

Alltel’s cellular network is based on CDMA technology, incompatible with AT&T’s GSM network. Alltel subscribers are expected to receive credit towards the purchase of new GSM equipment as Alltel’s network is retired.

AT&T says its acquisition will allow Alltel customers to enjoy a better wireless experience and also benefit AT&T customers who roam in Alltel service areas. But customers will likely lose access to Alltel’s service plans and will eventually be asked to choose a different plan from AT&T, potentially at a higher price.

The acquisition further reduces competition in the American wireless marketplace.