If your URL looks like this ...
http://mysite.com/myscript.php?name=theeper
where 'name' is the key and 'theeper' is the value.
You would maybe have a script that looks like this.
<?
echo $_POST['name'];
?>
If you are using PHP v 4+ with register_globals=off, the above would work.
If you have register_globals=on, you could do this...
<?
echo $name;
?>