Reference

http://www.x.org/ Curators of the X Window System.

http://www.x.org/Downloads_mirror.html Want to download the source to the latest revision of X? Start at this list of mirror sites.

http://www.xfree86.org/ Home of The XFree86 Project, Inc., which has provided a graphical interface for Linux for nearly 10 years.

http://www.kde.org/ The place to get started when learning about KDE and the latest developments.

http://www.gnome.org/ The launch point for more information about GNOME, links to new clients, and GNOME development projects.