Apologies if you're determined to use DOMDocument() in this, but since nobody has posted an answer so far...here's a script which uses simple_xml_load_file(), which I found quite easy to get to grips with.
<?php
$rss_array = array('http://rss.computerworld.com/computerworld/s/feed/topic/231', 'http://rss.computerworld.com/computerworld/s/feed/topic/230', 'http://rss.computerworld.com/computerworld/s/feed/topic/66', 'http://www.engadget.com/rss.xml', 'http://feeds.webservice.techradar.com/rss/new', 'http://feeds.arstechnica.com/arstechnica/index', 'http://www.notebookcheck.net/News.152.100.html', 'http://electronista.feedsportal.com/c/34342/f/626172/index.rss', 'http://www.anandtech.com/rss/pipeline/', 'http://www.digitimes.com/rss/daily.xml', 'http://feeds.feedburner.com/TechCrunch/', 'http://feeds2.feedburner.com/ziffdavis/pcmag/breakingnews', 'http://feeds.feedburner.com/Liliputing', 'http://feeds.slashgear.com/slashgear', 'http://feeds.feedburner.com/GizmagEmergingTechnologyMagazine', 'http://www.zdnet.com/news/rss.xml', 'http://feeds.feedburner.com/mobilityupdate', 'http://www.techmeme.com/feed.xml', 'http://www.notebookreview.com/rss.xml');
for ($i=0; $i<count($rss_array); $i++ ) {
$rssfeed = simplexml_load_file($rss_array[$i]);
foreach ($rssfeed->channel as $channel) {
echo '<h1>' . htmlentities($channel->title) . '</h1>';
echo '<p>' . htmlentities($channel->description) . '</p>';
echo '<p><a href="' . htmlentities($channel->link) . '">' .
htmlentities($channel->link) . '</a></p>';
echo '<input type="button" value=" >>> " onClick="downloadFileViaAjax(\'' . htmlentities($channel->link) . '\')">';
echo '<ul>';
foreach ($channel->item as $item) {
echo '<li><a href="' . htmlentities($item->link) . '">';
echo htmlentities($item->title) . '</a>';
// echo htmlentities($item->description) . '</li>';
echo '<input type="button" value=" >>> " onClick="downloadFileViaAjax(\'' . htmlentities($item->link) . '\')"></li>';
}
echo '</ul>';
}
}//fur ( $rss_array++ )
?>