Free Software Foundation:
      http://www.fsf.org

GNU is not UNIX:
      http://www.gnu.org

GNOME:
      http://www.gnome.org

KDE:
      http://www.kde.org

OpenSource Initiative:
      http://www.opensource.org

ONLamp:
      http://www.onlamp.com/pub/a/onlamp/2004/11/18/licenses.html

SourceForge.net:
      http://www.sourceforge.net

Wikipedia:
      http://es.wikipedia.org