I\'m using PHP 5.3.10. This is the code:
There is a PHP class on google code for validating email addresses:
http://code.google.com/p/php-email-address-validation
You can use it like
include('EmailAddressValidator.php');
$validator = new EmailAddressValidator;
if ($validator->check_email_address('test@example.org')) {
// Email address is technically valid
} else {
// Email not valid
}