<?
loop to figure out how many email there are, then loop, if static do numbered for loop
{
for loop to loop thru 50 emails, then loop back thru and get the next...so on
{
do the mail
sleep(5); //how ever long, 5 seconds
process other stuff if needed, then loop back up to next 50
}
}
?>
then have a cron job call the phppage using wget, you can search on yahoo for "run php page with cron" to find numerous tut's on that