Hi cbb,
I don’t maintain a listing of flexible polyurethane foam providers, either regionally or nationally, as that is ever-changing and much too large of a task for one person to attempt to keep up to date in an ever changing market.
Besides the polyurethane foam providers listed in the component post here, you could also inquire with CertiPUR-US to see if they have any recommendations in your area. You can also use resources like this one or this one and refine your search form there and contact some of these manufactures and see if they sell directly to the public or can provide you with a list of their retail outlets near your home. There is also an extensive list from ISPA here. Elite Comfort Solutions also has a large foam producer in your area (formerly called Elite Foams). You could also contact Latexco East in Lavonia, GA (they produce more than just latex).
You can also perform a forum search on Atlanta and see what other businesses have been discussed in that region which may be helpful to you.
Hopefully all of that information gives you a good start.
Phoenix