Software opensource gratuito:

http://www.opensourcemac.org/

http://www.apple.com/downloads/macosx/unix_open_source/

http://en.wikipedia.org/wiki/List_of_Macintosh_software

http://www.freemacware.com/category/open-source-mac-software/

http://usingmac.com/2008/11/12/100-free-applications