According to an article on pcworld, AT&T will achieve true nationwide coverage by the end of this year when it introduces their planned service that uses both mobile and satellite services.

Apparently, AT&T will resell satellite service and mobile phones from TerreStar Networks, a startup which is set to launch its first satellite on the 1st of July.

Furthermore, TerreStar is working on developing hybrid satellite/mobile handsets which have been designed to be roughly the same size as a smartphone. Once launched the TerreStar satellite will by 22,000 miles above the US and deliver the service across Canada and the United States.