Many, many posts on different RWA loops have mentioned the lack of free Internet access anywhere in the Marriott. So, thanks to a link from another blogger, I went to the Mall at Peachtree Center website.
"Peachtree Center offers FREE wireless internet connection in The Mall. With a battery-powered laptop, the internet is accessible in a "hot spot" of The Mall. Look for the designated areas in the South Food Court and near the Information Booth."