The links below are to software that is a viable alternative to more expensive and propriety software. Most of the software listed below was developed under a General Public License, GPL or Creative Commons licence. Others may not be a GPL product but the cost is low or free in most instances.
Web Browsers — Alternatives to IE
Archivers — File Compressors
Media Players
Windows Media Player
Winamp
iTunes
Quicktime
Divx
Real Player
General Applications — Miscellaneous Productivity applications
Open Office
Skype - Instant Messenger
Swish
Java
Flash Player
QQ - Instant Messenger
508 tested