I was trying to access $_GET variables in drupal. After a long search when i did not find any thing. I decide to give a try by writing a module which give the $_GET variables.
To my surprise drupal support the $_GET variables.
switch ($_GET['op']){
case 'action':
{your code here}
break;
case 'message':
{your code here}
break;
}
The URI parser is excellent it cleanly removes the path url which is available in arg(n) and the variables after ?op is cleanly stored in the $_GET['op']