you need to use sessions.
put session_start() at the start of every page, and define $_SESSION['variable'] as $_POST['variable'], instead of just $variable.
here's a dummy example i just set up to get ie6 treating session variables properly:
index.php
PHP Code:
<?
session_start();
$_SESSION['product1'] = 'sonic screwdriver';
$_SESSION['product2'] = 'HAL 2000';
echo '<a href="page2.php">The products have been registered</a>';
?>
<form method="post" action="page2.php">
<input type="submit" name="submit" id="submit" value="Log In" class="button" />
</form>
page2.php
PHP Code:
<?
session_start();
?>
Your chosen products are:
<ul>
<li><?= $_SESSION['product1']; ?></li>
<li><?= $_SESSION['product2']; ?></li>
</ul>
you'd just define the $_SESSION variables on page 2 instead of 1.
as for the ie6 thing, turn session.use_trans_sid on in your php.ini. ie 6 will start a new session every page load otherwise, because microsoft builds bad products.