Mail() tag problem

Hi there, I have just coded a simple mail script that sends a small text email from a php script (nice and easy!). The script is exactly the same as others I have running on the same server. The problem is it seems to take about 4 minutes for the page to reload saying thank you, the mail has been sent and for the mail to actually go. All my other scripts load within 10 seconds and the mail is sent. The only difference that I can think of is that the domain name that I'm using to host the script on the server is different to the domain name of my working scripts. Is there a configuration issue I need to sort out with mail() tag or sendmail? Is there anyway of forcing the mail() tag to send the mail and not wait to make sure it has gone, or does it have to get a response from the server stating the mail has been sent before the php script continues? thanks to any one who can help hamish