Character encoding and character sets are not that difficult to understand, but so many people blithely stumble through the worlds of programming without knowing what to actually do about it, or say "Ah, it's a job for those experts." No, it is not!
This document will walk you through determining the encoding of your system and how you should handle this information.
Doing this is more of a hit-or-miss process: depending on the software being used as a webserver and the configuration of that software, certain techniques may work, or may not work.
On Apache, you can use an .htaccess file to change the character encoding.
If you're feeling particularly courageous, you can use: ...which changes the character set Apache adds to any document that doesn't have any Content-Type parameters.