Open Source and Free Software
Understanding the meaning of the movement...
The following is a selection of essays, statements and definitions to help newcomers understand what is behind these movements. It is also an excellent refresher for those of us who are helping to further these projects.

What is Free Software? - As notated by the Free Software foundation
Why Software Should Not Have Owners - An Excellent Essay by Richard Stallman
What is Copyleft? - As notated by the Free Software foundation
free Software is More reliable! - As notated by the Free Software foundation

Sources for further reading, or research...

the Gnu ProjectThe GNU Project (pronounced guh-noo, like canoe) is an ongoing effort to develop a complete UNIX-like operating system which is free software: the GNU system. Variants of the GNU operating system, generally called GNU/Linux systems, are widely used today.

the Gnu ProjectThe founders of the GNU Project, FSF is dedicated to promoting computer users' rights to use, study, copy, modify, and redistribute computer programs. The FSF promotes the development and use of free software, particularly the GNU operating system.

(OSI) LogoThe Open Source Initiative (OSI) is a non-profit corporation dedicated to managing and promoting the Open Source Definition for the good of the community, specifically through the OSI Certified Open Source Software certification mark and program.