I want to place links in a web page to various documents (.ps, .pdf, .doc, .ppt, etc) without revealing the location of them on the server.
I'm not sure that your question really makes sense.
If you're trying to hide their URL then you can't. By definition this information has to be made available so that your web browser can actually fetch them. Even if you could find some really neat trick to hide them from Netscape and IE etc, I could write my own "browser" (ObPerl: using LWP, of course!) that would be able to get at the file.
If you mean that you want to hide the actual location of them on the server, ie not show that they're in /www/docs/ or whatever, then your webserver should take care of that for you. No-one can easily know what your base directory is without reading your config file, and you can always remap different URLs to point to different physical locations anyway.
Tony