Try this:
$url = "http://ecs.amazonaws.com/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=1DN1Y0GF2HTSA76NRQG2&Operation=BrowseNodeLookup&ResponseGroup=BrowseNodeInfo&BrowseNodeId=1000";
$xml = new SimpleXMLElement($url,null,true);
foreach ($xml->BrowseNodes->BrowseNode->Children->BrowseNode as $child)
{
echo $child->BrowseNodeId . " - " . $child->Name . "<br>";
}
Remember, print_r is your friend.