There is no single organization which can be said to head the Open Source Movement.  Rather, there are a number of different organizations which all pursue the same goal of freely distributable and freely modifiable source code, albeit by different means.  The Free Software Foundation pioneered the concept of free software in the 1980s and is "dedicated to eliminating restrictions on copying, redistribution, understanding, and modification of computer programs."  Other prominent organizations are opensource.org and the Debian Project.  For some examples of software which is based on the open source model, see the Linux Documentation Project and Netscape Communications which released its source code to the general public in 1998.