http://www.facebook.com/my_page_name
http://www.facebook.com/pages/my_page_name
http://www.facebook.com/my_page_ID

identifier = url.substring(url.lastIndexOf("/"))
graphUrl = "https://graph.facebook.com/" + identifier
urlJsonData = getGraphData(graphUrl)

url = http://www.facebook.com/southpark

url = http://www.facebook.com/6708787004

<?php

function getFacebookId($url) {

    $id =  substr(strrchr($url,'/'),1);

    $json = file_get_contents('http://graph.facebook.com/'.$id);

    $json = json_decode($json);

    return $json->id;

}


echo getFacebookId($_GET['url']);


?>