yeah do as n2casey said, and write a if conditional like this -
PHP Code:
if(strcmp($_GET['event'], 'delete') === 0 and !empty($_GET['usertodelete'])) {
// .. rest of processing
}
I suggest you use Zend Framework (framework.zend.com)
It makes PHP programming easy. You don't need to write common things like Db driver, path manipulator, etc.
You just code the App Logic.