sending mail with PHP

How to send mail with PHP and what does the server need to do this?
I want to make my own site referer.
Anyone knows the code?

Thanks,
Mare

http://www.php.net/manual/function.mail.php

Code:

---

        $to = "their@email.com";
        $from = "yours@email.com";
        $body = "Email message here"
        $headers = "From: $from\r\n";
        $headers .= "Reply-To: $from\r\n";
        $success = mail($to, "$subject", $body, $headers);

        if($success)
        {
                echo "Mail sent to $to";
        }

---

thanks!