CREATE TABLE `useronline` (
`id` INT( 10 ) NOT NULL ,
`ip` VARCHAR( 15 ) NOT NULL ,
`timestamp` VARCHAR( 15 ) NOT NULL
) ENGINE = MYISAM ;

<?php
if(!defined("WCDDL_GUTS"))
   exit;
   function online(){
$visitors_online = new usersOnline();
if (count($visitors_online->error) == 0) {
        echo $visitors_online->count_users() . " Users Online";
}
else {
    echo "Users online class errors:
<ul>\r\n";
    for ($i = 0; $i < count($visitors_online->error); $i ++ ) {
        echo "[*]" . $visitors_online->error[$i] . "\r\n";
    }
    echo "[/list]\r\n";
}
   }
?>

        class usersOnline {
           var $timeout = 120;
           var $count = 1;
           var $error;
           var $i = 0;
           function usersOnline () {
              $this->timestamp = time();
              $this->ip = $this->ipCheck();
              $this->new_user();
              $this->delete_user();
              $this->count_users();
           }
           function ipCheck() {
              if (getenv('HTTP_CLIENT_IP')) {
                 $ip = getenv('HTTP_CLIENT_IP');
              }
              elseif (getenv('HTTP_X_FORWARDED_FOR')) {
                 $ip = getenv('HTTP_X_FORWARDED_FOR');
              }
              elseif (getenv('HTTP_X_FORWARDED')) {
                 $ip = getenv('HTTP_X_FORWARDED');
              }
              elseif (getenv('HTTP_FORWARDED_FOR')) {
                 $ip = getenv('HTTP_FORWARDED_FOR');
              }
              elseif (getenv('HTTP_FORWARDED')) {
                 $ip = getenv('HTTP_FORWARDED');
              }
              else {
                 $ip = $_SERVER['REMOTE_ADDR'];
              }
              return $ip;
           }
           function new_user() {
              $insert = mysql_query ("INSERT INTO useronline(timestamp, ip) VALUES ('$this->timestamp', '$this->ip')");
              if (!$insert) {
                 $this->error[$this->i] = "Unable to record new visitor\r\n";         
                 $this->i ++;
              }
           }
           function delete_user() {
              $delete = mysql_query ("DELETE FROM useronline WHERE timestamp < ($this->timestamp - $this->timeout)");
              if (!$delete) {
                 $this->error[$this->i] = "Unable to delete visitors";
                 $this->i ++;
              }
           }
           function count_users() {
              if (count($this->error) == 0) {
                 $count = mysql_num_rows ( mysql_query("SELECT DISTINCT ip FROM useronline"));
                 return $count;
              }
           }
        }