Ecco il codice:

<?PHP
/* Easy refer-a-friend
Original script by burt [ burt@dotdragnet.co.uk ]
Modifications by sandman [ sandman@idscotland.co.uk ]
Traduzione italiana [ farlimas@altervista.org ]

If you modify this script to make it more functional,
please let us know so that we can update ours as well ! */

//set variables

// Your site name for use in the email
$site_name="http://www.fdiodato.tk";
// Your message for the email
$text="Ciao, ho trovato questo bel sito che ti segnalo $site_name";
// Title of email
$title="Un messaggio dal tuo amico $sendername";
// Thank you page for users
$thankspage="http://fdiodato.altervista.org/grazieita.htm";

// START CODE, DO NOT CHANGE ANYTHING BELOW THIS LINE

// check email addresses

$x1 = ereg("^[0-9a-z]([-_.]?[0-9a-z])*@[0-9a-z]([-.]?[0-9a-z])*\\.[a-z]{2,3}$",$senderemail);
if($x1==0)
# if no valid email address entered, display no email message
{
echo "<div align=center>Devi inserire un tuo indirizzo email valido.
<a href=javascript:history.back(-1)>Ritorna al form</a>.</div>";
exit;
}

if ($email<>"") {
$x2 = ereg("^[0-9a-z]([-_.]?[0-9a-z])*@[0-9a-z]([-.]?[0-9a-z])*\\.[a-z]{2,3}$",$email);
if($x2==0)
# if no valid email address entered, display no email message
{
echo "<div align=center>!!ERRORE!!Il primo indirizzo email non &egrave; valido.
<a href=javascript:history.back(-1)>Ritorna al
form</a>.</div>";
}
}

if ($email2<>"")
{
$x3 = ereg("^[0-9a-z]([-_.]?[0-9a-z])*@[0-9a-z]([-.]?[0-9a-z])*\\.[a-z]{2,3}$",$email2);
if($x3==0)
# if no valid email address entered, display no email message
{
echo "<div align=center>!!ERRORE!!Il secondo indirizzo email non &egrave; valido.
<a href=javascript:history.back(-1)>Ritorna al
form</a>.</div>";
}
}

if ($email3<>"")
{
$x4 = ereg("^[0-9a-z]([-_.]?[0-9a-z])*@[0-9a-z]([-.]?[0-9a-z])*\\.[a-z]{2,3}$",$email3);
if($x4==0)
# if no valid email address entered, display no email message
{
echo "<div align=center>!!ERRORE!!Il terzo indirizzo email non &egrave; valido.
<a href=javascript:history.back(-1)>Ritorna al
form</a>.</div>";
}
}
if (($x2!=0) || ($x3!=0) || ($x4!=0))
{
mail("$email", "$title", "$text", "From: \"$sendername\" $senderemail\n");
mail("$email2", "$title", "$text", "From: \"$sendername\" $senderemail\n");
mail("$email3", "$title", "$text", "From: \"$sendername\" $senderemail\n");

// return thank you page
header("Location: $thankspage");
}

?>