If you have encoding problem when using mail(). You could consider using mb_send_mail(). Here is an example written by Taslim Mazumder Sohel.

<?php

/**
 * @name: sendMail
 * @author Taslim Mazumder Sohel
 * @mailsohel62@yahoo.com
 * Function for sending email
 * with Japanese Email Body, Subject, Sender Name.
 *
 * @param String $to         : Receiver mail address.
 * @param String $subject    : email subject.
 * @param int    $body       : mail body text.
 * @param array  $from_email : Sender mail address.
 * @param array  $from_name  : Sender Name.
 *
 */
function sendMail($to, $subject, $body, $from_email,$from_name) {
  $headers  = "MIME-Version: 1.0 \n" ;
  $headers .= "From: " .
         "".mb_encode_mimeheader (mb_convert_encoding($from_name,"ISO-2022-JP","AUTO")) ."" .
         "<".$from_email."> \n";
  $headers .= "Reply-To: " .
         "".mb_encode_mimeheader (mb_convert_encoding($from_name,"ISO-2022-JP","AUTO")) ."" .
         "<".$from_email."> \n";
   
  $headers .= "Content-Type: text/plain;charset=ISO-2022-JP \n";

  /* Convert body to same encoding as stated in Content-Type header above */
  $body = mb_convert_encoding($body, "ISO-2022-JP","AUTO");
     
  /* Mail, optional paramiters. */
  $sendmail_params  = "-f$from_email";
     
  mb_language("ja");
  $subject = mb_convert_encoding($subject, "ISO-2022-JP","AUTO");
  $subject = mb_encode_mimeheader($subject);

  $result = mail($to, $subject, $body, $headers, $sendmail_params);
        
  return $result;
}

?>

Done =)

Reference:

• PHP Manual – mb_send_mail
• PHP Manual – mb_convert_encoding
• PHP Manual – mb_language
• PHP Manual – mb_encode_mimeheader