Firstly I would recommend getting the latest version which is attached to the post above.
OK what you need to do is this
PHP:
<?php
include "class.rss_parser.php";
$parser = new RSS_Parser('http://newsrss.bbc.co.uk/rss/newsonline_uk_edition/uk_politics/rss.xml', 6);
$array_of_items = $parser->fetchAndParseXML();
// you now have an array of news item titles. If you wanted a list
echo "<ul>\n";
foreach ($array_of_items as $title) {
echo "<li>" . $title ."</li>\n";
}
echo "</ul>\n";
?>
The important thing to understand is that RSS_Parser is something called an Object. You treat it much like you would a string, integer or any other variable. I have hidden away the gritty inner workings of parsing RSS and exposed only three real functions for you to use and one constructor function.
The things you can do are
// create a new RSS_Parser object, so that you could parse a number of different
// feeds by creating different 'instances' or copies of the RSS_Parser
// This is the Constructor function, it must be called before any of the other functions
$parser = new RSS_Parser($url_of_feed, $number_of_entries);
// Tell the parser to download the feed
$parser->fetchXML();
// Tell the parser to parse the feed and return you an array of item titles
$array = $parser->parseXML();
// Tell the parser to download the feed and then parse it, returning you an array of item titles
$array = $parser->fetchAndParseXML();
pretty much anything beginning with a double underscore should be considered hidden and for use exclusively by the parser itself.
I hope that helps and doesn't sound too much like some ancient language