Austin, Texas has a number of small shops that offer free wifi. Probably the most widespread free wifi in the area is the Schlotzskys deli chain. They are a fairly large chain headquartered here in Austin with locations throughout the US. All of their Austin locations have free wifi access and their website mentions that some in Atlanta and Houston do as well.
http://www.schlotzskys.com/wireless.html
Another place that offers it is a local group of movie theatres, the Alamo Drafthouse. They are a fantastic place to see a movie because they have a full menu (including beer and wine) and waitstaff service at your table. They sell out many of their shows and you often need to be there 45 minutes ahead of time so it can help kill some time before the movie starts.
Actually just ate lunch at Schlotzskys this afternoon and brought the Axim along. They had a fairly long registration process with 15-20 questions you had to answer, but after that it was great.