Currently there are two that I know of. "Shaintiques" a forum member here, and founder of the FPP(Free Pipe Project) runs two clubs, one in Douglasville, and the other in Hiram. I live in Kennesaw and recently attended the one in Hiram last week. I haven't gone to the Douglasville club meeting as of yet, but I intend to.
I can't remember the times they meet, but you can PM Shaintiques for more information. Also search for Atlanta pipe club thread in the pipe clubs section and you can get more info.