If you want to view PostScript documents with a Web Browser (e.g. Netscape, Mosaic,...) you should install Ghostscript and possibley Ghostview. If you are using a Mac, Ghostscript should be sufficient (the Mac version already has a Graphical User Interface (GUI)), but for Unix or MS-DOS you will probably also want to get Ghostview to serve as the user interface to Ghostscript. Instructions for setting up Ghostview to be your "external viewer" for PostScript documents on Unix machines are given below.
You can get Ghostscript and Ghostview from the sources listed here. Installation instructions are generally included in the distribution.
Ghostscript is now distributed in two different versions, with two different licenses. The Aladdin version, distributed by Aladdin Enterprises, is more recent and is covered by the Aladdin Ghostscript Free Public License, which prohibits commercial distrubution (unless you get a commercial license from Artifex Software Inc., which is currently the only entity authorized by Aladdin to grant such licenses). The GNU version is the Aladdin version of about a year ago, and is covered by the GNU Public License. See the README file for more information.
application/PostScript; ghostview %s
Netscape (version 1.1 or later), Mosaic (2.4 or later) and current beta
versions of Lynx will take care of unpacking files compressed with the
Unix compress utility (files ending in .Z) or the GNU gzip utility
(files ending in .gz), though some versions of Mosaic seem to have
problems getting this step right.
If you are using some other browser (OmniWeb, Microsoft Internet Explorer) then you may want to look at the instructions in the XXX archives at Los Alamos (below).