Check these sites for a wealth of information on all sorts of natural gas topics.

Basic natural gas information including exploration, delivery, the financial aspects of our nation's natural gas market and dozens of other topics:
NaturalGas.org
The Energy Information Administration

Calculating your base rate and questions about DDDC:
Atlanta Gas Light Company

Compare gas marketer prices:
Georgia Public Service Commission

Just what does gas deregulation mean?
Georgia Public Service Commission