Getting data from XML

Hey People, I was wondering if anyone could point me to an example or give me an example of data extraction from an XML document where you do not necessarily know the contents of the XML document. I am using PHP 5 RC3 and can see a lot of references to methods like getelementbytagname or getbyid etc but what if the data I am getting is not what I expected however I still want to display it. How do I go about this. Thanks in advance, Eamon.