If you're in the situation you want one url to redirect to another url (want a bunch of domains to point to your primary website, or want a 404 page to return the user to the front page) you can do it very simply with PHP and the header() function. the syntax is:

<?php header("Location: http://www.newurl.com/"); ?>

Put that line as the very first line in an otherwise empty index.php and change newurl.com to wherever you want the user to go. This is a seamless way of redirecting users to another location without mucking with html meta-refresh tags.