The current version of XFree86 is 4.2.0 as of this writing. It can be downloaded as source or binaries. It is generally recommended to download the binaries these days. See http://www.XFree86.org for the lastest official information on installation of XFree86. Later in this document, I describe only the very basic procedure for compiling and installing from the source.
XFree86 source code comes in three files:
Doctools is the DocBook SGML package used by XFree86 to prepare the X documentation. Utils contains the source for the "extract" program, which is a modified GNU tar with gzip support. Extract is only important if you are installing a binary distribution of XFree86 on top of your existing XFree86 to upgrade it. Extract unlinks old existing files that are being extracted/updated instead of skipping them. Extract comes with the binary distributions so utils.tgz is only important for making your own binary distribution.
You can download XFree86 from its ftp site: ftp://ftp.xfree86.org/
XFree86 includes GLX, the OpenGL X interface functions. Each window system has to provide the platform-specific interfaces between OpenGL and the window system for mapping a GL rendering context to a window system widget. Recent versions of XFree86, like version 4.2.0, now also include libGLU and the OpenGL manual pages.