Custom Error Documents

Create a text file called .htaccess with content similar to the following (provide a valid URL for each ErrorDocument):

ErrorDocument 404 http://www.domain.com/404.html
ErrorDocument 500 http://www.domain.com/500.html

Put the .htaccess file in your public_html directory. If the URLS in the .htaccess are valid, you can test the 404 ErrorDoc by going to an invalid URL in your webspace (eg: http://www.domain.com/this/does/not/exist.html)