[ChristGuy]

I'd say using sessions...

Basically...

at the top of protected pages:

PHP Code:

<?php

  if (!isset($_SESSION["username"]))

  {

    Header('Location: login.php');

  }

?>

To register the variables:

PHP Code:

<?php

  // If the user is valid

  if (IsValidUser($Username))

  {

    $_SESSION["username"] = $Username;

  }

  else

  {

    echo "Invalid user"

  }

?>

To logout

PHP Code:

<?php

  $_SESSION = array();

  Session_destoy();

?>

Hope that helps...