The latest release of the original X11 distribution can be obtained from ftp.x.org, or see http://www.x.org/download.htm for a list of ftp mirror sites. Most free systems now use the XFree86 distribution. XFree86 is available from ftp.xfree86.org/pub/XFree86, or see the www.xfree86.org web site for information on mirror ftp sites.