Here are some links to websites and software that may be useful additional sources of information in your research.
ArcGis Download from Brown Computing and Information Services allows all Brown users on-campus access to parts of the ArcGIS package that require a licence purchace.
FreeGIS is constantly updated with new free GIS programs and plugins.
GeoCommunity-Software has software downloads and information as well as discussion boards, reviews, and a connection to the greater GeoCommunity website.
GIS Development- Free Software Downloads is an extensive download, link, and information site.
MapCruzin is another website that provides links to several free software programs and information.