i am doing shopping cart with google checkout. but upto now i didnot integrated google checkout. so give me the sample code. it will helps me a lot. actually i integrated paypal already like below

<form name="frmpay" method="post" action="success.php">
    <input type="hidden" name="business" value="" />
    <input type="hidden" name="cmd" value="_xclick" />
    <input type="hidden" name="image_url" value="https://www.paypal.com/en_US/i/btn/x-click-but22.gif" />
    <input type="hidden" name="return" value="success.php" />
    <input type="hidden" name="cancel_return" value="error.php" />
    <input type="hidden" name="currency_code" value="GBP" />
    <input type="hidden" name="lc" value="UK" />
    <input type="hidden" name="no_shipping" value="1">
    <input type="hidden" name="item_name" value="<?=$res_item[name]?>" />
    <input type="hidden" name="amount" value="<?=$_SESSION['amt']?>" />
    <?php /*?><input type="hidden" name="shipping" value="<?=$_POST["shipping"]?>" /><?php */?>
    <input type="hidden" name="quantity" value="1" />

exactly like this how can i integrate google checkout. how can i return success page after payment in google checkout.

yes i found html formatted code but after successful payment how to redirect successpage which is in my website? actually what is the parameter to use for redirect to specific url after successfull payment?
this is my code

<form method="POST" name="frmpay"
  action="google merchantid"

  <input type="hidden" name="item_name_1" value="<?=$res_item['name']?>"/>
  <input type="hidden" name="item_description_1" value="Online Order"/>
  <input type="hidden" name="item_quantity_1" value="1"/>
  <input type="hidden" name="item_price_1" value="<?=$_SESSION['amt']?>"/>
  <input type="hidden" name="item_currency_1" value="GBP"/>