var_dump($xml);
outputs:

Revision: object(SimpleXMLElement)#4 (4) {
  ["@attributes"]=>
  array(1) {
    ["revision"]=>
    string(2) "31"
  }
  ["author"]=>
  string(5) "kobaz"
  ["date"]=>
  string(27) "2007-03-26T16:53:20.938183Z"
  ["msg"]=>
  string(56) "stuff"
}


how do i access attributes of xml

$xml->attributes is empty