How to XML to PHP?

I have the following Simple XML Data:

SimpleXMLElement Object
(
    [source] => SimpleXMLElement Object
        (
            [@attributes] => Array
                (
                    [mount] => /FavoriteFM
                )

            [Listeners] => 38
            [listener] => Array
                (
                    [0] => SimpleXMLElement Object
                        (
                            [IP] => 0.0.0.0
                            [UserAgent] => curl/7.19.7 (i386-redhat-linux-gnu) libcurl/7.19.7 NSS/3.16.2.3 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2
                            [Connected] => 201471
                            [ID] => 2972275
                        )

I want to show [IP].

So I have this PHP script:

<?php

$url = "http://ift.tt/1IkJkvH";
$xml = simplexml_load_file($url);
echo "<pre>";
print_r($xml);
 $IP = $xml->listener->IP;
 echo $IP[0];

?>

But it's not working. How can I display display IP in the proper way?