php DOMDocument getAttribute

I am using the php DOMDocument to parse through an RSS 2.0 feed. Everything is working fine except for this line.

$image = $node->getElementsByTagName('itunes:image')->item(0)->getAttribute('href');

Where $node is the <item> element.

$image is empty after the function.

Edit:

The following is also returning empty...

$node->getElementsByTagName('itunes:summary')->item(0)->nodeValue

So does this have something to do with the : in the node name?

Learn about namespaces, and use getElementsByTagNameNS.

$node->getElementsByTagNameNS('http://www.itunes.com/dtds/podcast-1.0.dtd', 'summary');