Starting June 10, 2010 the North American Numbering Plan Administration will introduce a new area code covering the same Alabama area currently served by area code 256 (Athens, Decatur, Florence, Huntsville, etc). The new area code is 938.
Starting November 7, 2009 a permissive dialing period began during which calls within area code 256 may be dialed using both the 7 digit and 10 digit dialing formats. The permissive dialing period will end on June 5, 2010. After June 5 all calls within the area covered by area codes 256 and 938 must be dialed using the 10 digit format.
NANPA announcement and map of the new overlay complex (in PDF format)