Downloading Cygwin/X 1.0.4 from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this software available. We recommend checking the downloaded files with any free antivirus. Also the program is known as "CygwinX". The program lies within Internet & Network Tools, more precisely Network Tools. The most popular versions of the tool are 11.0 and 1.0. This free software was originally created by Cygnus.
From the developer:
Cygwin/X consists of an X server, X libraries, and nearly all of the standard X clients, such as xterm, xhost, xdpyinfo, xclock, xeyes, etc. Cygwin/X, as the name implies, uses the Cygwin project which provides a UNIX-like API to Xlib and X clients, thereby minimizing the amount of porting required.
You may want to check out more software, such as WMS Client for Arcview Beta, Usage Agent or SigX, which might be related to Cygwin/X.