XML Parsing in PHP (Easy) -- Ignore specific tags?

I’m currently testing out this script – http://www.kirupa.com/web/xml_php_parse_beginner.htm to write my xml data to another page for search engine indexing.

However, because of the size of the xml files, there are some tags I’d like to strip out to shorten the amount of data that is written to the resulting page. How do I tell the xml parser to ignore this list of tags and only write information for the rest of them?

Thanks!