...uno a caso (preso dal sito della zend)

<?php


$email="john@zend.com";

if(!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-
]+)*(\.[a-z]{2,3})$", $email) {

echo "The e-mail was not valid";

} else {

echo "The e-mail was valid";

}

?>


M