From the latest Epidemiology Monitor.
"With improvements in commercial software, such as SAS, SPSS, Stata, and others, is there still a need for free epidemiologic software?
Commercial software can be expensive, may have a steep learning curve, and may not provide certain types of desired analyses. In this article information on three free epidemiologic/statistical programs is provided: Epi Info, OpenEpi, and WinPepi."
In addition, you may also be interested in perusing Wikipedia’s List of Statistical Packages and Comparison of Statistical Packages.