Taking the GRE in Florence , South Carolina: 

 The test is given at the center listed below. As of 11/12/2014 the phone number works. The GRE is given continuously and you can sign up by going to the ETS web site.  https://mygre.ets.org/greweb/action/RegPortal 

see below for web page example of sign up list. 

Florence - 5170

Prometric Testing Center
2141 C Hoffmeyer Road
West Gate Office Park
Florence , South Carolina 29501 -
United States of America
(843)667-3227