Passing a variable through PHP with a URL

i have two lines of code in insert.php that read:

$card = mysql_insert_id();
$Body .= "http://www.reintroducing.com/apnw/load.php?card=$card
";

now, the link generated comes out in the e-mail that is sent through the script as http://www.reintroducing.com/apnw/load.php?card=8 lets say for instance. then i have load.php that i want to use the value of $card (8 in this example) to run an SQL query and load up all information from the table ecard that has to do with record 8 and display it. how would i go about doing this?