Here is long list of open-source and free software for the Windows/mac platform. Please note that we don't consider  “ad-supported” free version as FREE. It has to be FULL and FREE, or http://www.viagrabelgiquefr.com/ open source. BSD or Linux users are already enjoying free software, but others might not be aware that a most of these are multi-platform software.

http://heliologue.com/free-software/