loop newsletter

Hi, I've made a little newsletter in php3. When I send the email, 750 persons (adresses are in a mysql database) receive the mail, I mean should receive: I've been testing the script with 5 users and it all looked ok. But now it seems that the loop for sending 750 emails times out... anyone with a sollution? I was thinking of putting the loop in the background (don't know how though) or something like that? thanx a lot! Juan :o)