See how many ppl are on your site

<?php
// ######################################
//               Toni Zen
//                  (c)
//                2.o.o.8
// ######################################

// Database connection and selection
mysql_connect("localhost", "root", "") or die("Cannot connect");
mysql_select_db("mydatabase") or die("Cannot select database");

// Query for the visitors IP address
$ipQuery = mysql_query("SELECT * FROM user_online WHERE ipaddress = '" . $_SERVER['REMOTE_ADDR'] . "' LIMIT 1");

// Have they visited before?
if(mysql_num_rows($ipQuery) == 1)
{
    // They have visited before
    // Update last active time
    mysql_query("UPDATE user_online SET lastactive = " . time() . " WHERE ipaddress = '" . $_SERVER['REMOTE_ADDR'] . "' LIMIT 1");
}
else
{
    // They have not visited before
    // Insert new row
    mysql_query("INSERT INTO `user_online` VALUES ('" . $_SERVER['REMOTE_ADDR'] . "', " . time() . ")") or die(mysql_error());
}

// Delete any old records (where lastactive < NOW - 5 Mins)
mysql_query("DELETE FROM user_online WHERE lastactive < " . (time() - 300)) or die(mysql_error());

// Query all views
$allViewQuery = mysql_query("SELECT * FROM user_online");

// Get the row count
$onlineCount = mysql_num_rows($allViewQuery);

echo "There is currently " . $onlineCount . " user(s) online";
?>