¿How can I customize my 404 error page?

I want to set my own 404 error page. How can I do it? Sorry if my english isn't good, I'm spanish. :o Thanks! :):p;)

You have to create your custom error page in your website root and call the file not_found.html or not_found.php

Here you can find more informations: http://forum.en.altervista.org/faqs/...pages-how.html