I love studying the ancient tribes of Georgia, as well as the historic tribes that existed in Georgia after the European contact. I have enjoyed reading Max White's The Archaeology and History of the Native Georgia Tribes. White is a professor of anthropology and archaeology at Piedmont College in the Georgia Mountains. This book takes the readers back to the PaleoIndian cultures that existed in the state.
More recently, I have been exploring a website called Lostworlds. It is located at http://www.lostworlds.org/. The site is maintained by professors from Georgia State University and was created by a former graduate student there who did his master's thesis documentary on archaeology-related topics in Georgia. The site focuses on the ancient and native cultures of Georgia and Florida. One recent posting on the site discusses evidence that Creek Indians of Georgia could have originated in Western Mexico. Among the pieces of evidence they site are pottery connections, mound connections, and effigies. The article is at this link, and they do such a wonderful job that I would rather you read it straight from the source.