PHP Script to send email with no timeout - php

Question

I am using this code to send email to my list using my server.
after a while as my list of email is large, the script get timeout.
is there a solution to this problem?
other thing i don't want to overload the server. Is there a code i can add to my script to load each email with a time between each line?
here is the php script i am using
<?php
$emailaddress = file("email-list.txt"); // load from a flat file, assuming 1 email per line in the file
$emailsubject = "[title] title of my email";
$emailbody = file_get_contents("email-content.html");
$fromaddress = "my#3emailserver.com";
$i = count($emailaddress);
$z = 0;
// here we check how many email address's we have, if its is 0, then we don't start the email function
if ($i != 0)
{// start if
// Lets loop until we reach the count from email address arrar
while ($i != $z)
{// start while
// here we send the email to the varables from above, using the email array incrament
mail($emailaddress[$z], $emailsubject, $emailbody, "From: " .$fromaddress. "\nX-Mailer: PHP 4.x");
// lets echo out that the email was sent
echo $z + 1 . " out of " . $i . " emails sent. (" . $emailaddress[$z] . ")<br>";
// increment the array one, so we get a new email address from the array
++$z;
}// end while
}//end if
else
{//start else
// we echo out that no emails where found in the array and end the script
echo "Warning: No emails in array.";
}// end else
?>

Answer 1

use
// sleep for 10 seconds
sleep(10);
after mail fire.

Answer 2

By default in php.ini, max_execution_time is set to 30 seconds. (check this in your php.ini)
Use set_time_limit function to alter that time (0=NOLIMIT):
set_time_limit(0);
Or use ini_set function:
ini_set('max_execution_time', 0);