I have created a simple php mailing script seeing a tutorial. But the problem is the script works but the email doesn't go. I got stuck with the mail host thingy. The guy uses his mailhost code like

ini_set("SMTP", "mailhost.*******.co.uk");

So I got stuck with this, what should be my mailhost, I have a domain with hosting. The provider just gave me three addresses which are


So how should I write the code, and I also got 10 POP3 email, i made some email accounts with it but how can I send the emails?

here is my code for index.php and send.php:

Code PHP:
require ('connect.php');
echo "<h1>Mailing List</h1> Send to <p>";
echo "<form action='send.php' method='GET'>";
//setup variable
$mailcount = 0;
$namecount = 0;
$get = mysql_query("SELECT * FROM mailinglist where send='1'");
while ($getrow = mysql_fetch_assoc($get))
echo "<input type = 'checkbox' name='mail_".$mailcount++."' value'".$getrow['email']."' CHECKED><br>".$getrow['firstname']." ".$getrow['lastname']." (".$getrow['email'].")<br>";
echo "</form>"

here is send.php

Code PHP:
require ('connect.php');
//change php.ini SMTP file
ini_set("SMTP", "mailhost.*******.co.uk");  <-------This line, please help
//standard mail header
$headers = "foodecrp@split.starhostbd.com";
//get message
//loop through
for($x=0; $x<count($_GET);$x++)
   if ($_GET["mail_$x"])
	//mail setup
		$to = $_GET["mail_$x"];
		$subject = "Newsletter";
		$body = "Dear ".$_GET["name_$x"]."
		\n\n $message \n\n
		mail($to, $subject, $body, $header);
echo "All email has been processed.";