KGhostView is part of the KDE 3 project, details of which can be found at http://www.kde.org.
To use KGhostView, you must have the Ghostscript program as well as KDE 3 installed on your machine. The Ghostscript home page is at http://www.cs.wisc.edu/~ghost/
Most distributions will include KGhostView, but if you want to roll your own the source code can be found in the kdegraphics package on ftp://ftp.kde.org/pub/kde/, the main ftp site of the KDE project.
In order to compile and install KGhostView on your system, type the following in the base directory of the KGhostView distribution:
%
./configure
%
make
%
make install
Since KGhostView uses autoconf and automake you should have no trouble compiling it. Should you run into problems please report them to the KDE mailing lists.