以前见到的PHP邮件功能，不错还是不错的。

<?
  /* Pop3 Functions.
     Smtp Functions. [Added later, going to split]

     For a real example take a look at:
     http://www.triple-it.nl/pop3/

     I have just started to explore the world of PHP3,
     so excuse (and correct me :) if I'm doing something wrong.

     Unk. (rgroesb@triple-it.nl)
   */

  function pop3_open($server, $port)  
  {
    global $POP3_GLOBAL_STATUS;

    $pop3 = fsockopen($server, $port);
    if ($pop3 <= 0) return 0;

    $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);

    if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

    return $pop3;
  }

  function pop3_user($pop3, $user)
  {
    global $POP3_GLOBAL_STATUS;

    fputs($pop3, "USER $user");
    $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);
    
    if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

    return 1;
  }

  function pop3_pass($pop3, $pass)
  {
    global $POP3_GLOBAL_STATUS;

    fputs($pop3, "PASS $pass");
    $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);
    
    if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

    return 1;
  }
  
  function pop3_stat($pop3)
  {
    global $POP3_GLOBAL_STATUS;

    fputs($pop3, "STAT");
    $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

    if (!eregi("+OK (.*) (.*)", $line, $regs)) 
        return 0;

    return $regs[1];
  }

  function pop3_list($pop3)
  {    
        global $POP3_GLOBAL_STATUS;
  
        fputs($pop3, "LIST");
        $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

    $i = 0;
    while  (substr($line  =  fgets($pop3, 1024),  0,  1)  <>  ".")
    {
        $articles[$i] = $line;
        $i++;
    }
    $articles["count"] = $i;

    return $articles;
  }

  function pop3_retr($pop3, $nr)
  {
        global $POP3_GLOBAL_STATUS;
  
        fputs($pop3, "RETR $nr");
        $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

        while  (substr($line  =  fgets($pop3, 1024),  0,  1)  <>  ".")
        {
                $data[$i] = $line;
                $i++;
        }
        $data["count"] = $i;

        return $data;
  }

  function pop3_dele($pop3, $nr)
  {
        global $POP3_GLOBAL_STATUS;

        fputs($pop3, "DELE $nr");
        $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

        return 1;
  }

  function pop3_quit($pop3)
  {
        global $POP3_GLOBAL_STATUS;

        fputs($pop3, "QUIT");
        $line = fgets($pop3, 1024);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] = substr($line, 0, 1);
        $POP3_GLOBAL_STATUS[$pop3]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($POP3_GLOBAL_STATUS[$pop3]["LASTRESULT"] <> "+") return 0;

        return 1;
  }

  function smtp_open($server, $port)
  {
        global $SMTP_GLOBAL_STATUS;

        $smtp = fsockopen($server, $port);
        if ($smtp < 0) return 0;

        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "2") return 0;

        return $smtp;
  }

 
  function smtp_helo($smtp)
  {
        global $SMTP_GLOBAL_STATUS;

    /* 'localhost' always works [Unk] */
        fputs($smtp, "helo localhost");
        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "2") return 0;

        return 1;
  }
 
  function smtp_ehlo($smtp)
  {
        global $SMTP_GLOBAL_STATUS;

    /* Well, let's use "helo" for now.. Until we need the
          extra func's   [Unk]
     */
        fputs($smtp, "helo localhost");
        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "2") return 0;

        return 1;
  }

  function smtp_mail_from($smtp, $from)
  {
        global $SMTP_GLOBAL_STATUS;

        fputs($smtp, "MAIL FROM: <$from>");
        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "2") return 0;

        return 1;
  }
 
  function smtp_rcpt_to($smtp, $to)
  {
        global $SMTP_GLOBAL_STATUS;

        fputs($smtp, "RCPT TO: <$to>");
        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "2") return 0;

        return 1;
  }

  function smtp_data($smtp, $subject, $data)
  {
        global $SMTP_GLOBAL_STATUS;

        fputs($smtp, "DATA");
        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "3") return 0;

    fputs($smtp, "Mime-Version: 1.0");
    fputs($smtp, "Subject: $subject");    
    fputs($smtp, "$data");
    fputs($smtp, ".");
        $line = fgets($smtp, 1024);
    if (substr($line, 0, 1) <> "2")
        return 0; 

        return 1;
  }
 
  function smtp_quit($smtp)
  {
        global $SMTP_GLOBAL_STATUS;

        fputs($smtp, "QUIT");
        $line = fgets($smtp, 1024);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] = substr($line, 0, 1);
        $SMTP_GLOBAL_STATUS[$smtp]["LASTRESULTTXT"] = substr($line, 0, 1024);

        if ($SMTP_GLOBAL_STATUS[$smtp]["LASTRESULT"] <> "2") return 0;

    return 1;
  } 
  

  
/*
 $pop3 = pop3_open("localhost", "110");
 if (!$pop3) {
    printf("[ERROR] Failed to connect to localhost<BR>");
    return 0;
 }
 
 if (!pop3_user($pop3, "unk")) {
    printf("[ERROR] Username failed!<BR>");
    return 0;
 }
 
 if (!pop3_pass($pop3, "secret")) {
    printf("[ERROR] PASS failed!<BR>");
    return 0;
 }

 $articles = pop3_list($pop3);
 if (!$articles) {
    printf("[ERROR] LIST failed!<BR>");
    return 0;
 }
 
 for ($i = 1; $i < $articles ["count"] + 1; $i++)
 {
    printf("i=$i<BR>");
    $data = pop3_retr($pop3,$i);
    if (!$data) {
        printf("data goes wrong on '$i'<BR>");
        return 0;
    }
    
    for ($j = 0; $j < $data["count"]; $j++)
    {
        printf("$data[$j]<BR>");
    }
 }
 */
 
 
?>