如何发送回复邮件与以下PHP代码

我想给客户发一封邮件，感谢您的回复。请帮我如何发送?我在这里发送代码，请检查代码。

 <? session_start();
    require_once('../includes/recaptchalib.php');
    $privatekey =PRIVATE_KEY;
    $resp = recaptcha_check_answer ($privatekey,
                                $_SERVER["REMOTE_ADDR"],
                                $_POST["recaptcha_challenge_field"],
                                $_POST["recaptcha_response_field"]);
    if (!$resp->is_valid) {
    // What happens when the CAPTCHA was entered incorrectly
    // die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." ."(reCAPTCHA said: " . $resp->error . ")");
          $REF_URL=$_SERVER['HTTP_REFERER'];
          if(strpos($REF_URL, '?v='))
            $URL=$REF_URL;
            else
          $URL=$_SERVER['HTTP_REFERER']."?v=1";
         echo "<meta http-equiv='"refresh'" content='"0;url=".$URL."'"/>";
    } else {
    // Your code here to handle a successful verification
    //echo "CAPTCHA verified ";
    foreach ($_REQUEST as $key=>$val){
    $_SESSION['contactvars'][$key] = $val;
    }
    foreach ($_REQUEST as $key=>$var){
    if ($key != 'PHPSESSID' && $key != "__utmz" && $key != "__utma" && $key != "__utmc" && $key != "__utmb"){
        if (is_array($var)){
            foreach ($var as $k=>$v){
                $message .= "$key: $v 'n";
                }//each array key
            }//is an array
        else {  
            $message .= "$key: $var 'n";
            }//not an array
        }//not phpsessid
    }//each request
    if (mail("mark@potterhandy.com", "Contact request from PotterHandy.com", $message, "From: PotterHandy.com <info@potterhandy.com>" ."'r'n" . "Cc: dave@rewebsitepro.com" .  "'r'n" . "Cc: stan@potterhandy.com" .  "'r'n" . "Cc: michaelhandy@potterhandy.com")){
    unset($_SESSION['contactvars']);
    header("Location: ../requestsent");
    }
     }

    ?>

感谢您给客户的回复邮件。请帮帮我。谢谢。