Free software or Open Source is about users' freedom to run, copy, distribute, study, change and improve the software. While free software and open source definitions are different, note that in the vast majority of cases a license that meets the OSI’s open source definition also meets the FSF’s free software definition.
http://www.fsf.org/about/what-is-free-software
http://www.opensource.org/docs/osd
More about differences between FSF and OSI approved licenses can be found in the following paper “Capability Coordination in Modular Organization: Voluntary FS/OSS Production and the Case of Debian GNU/Linux” at http://bit.ly/aCoz19 and at my blog entry about approval processes http://bit.ly/cnR4uX
