auto-updating site?

I am looking into possibly starting a couple of these sites but i have no idea on how. I see a few sites listed in the BST section reguarding auto-updating site and would like to own some but made about what I want for a niche. I am just wondering what sorta scripts and what not I need to get them running.

 

RSS feeds - here is one i use for a PHP site

Web reference
</span>
<div class="t11g" id="size">
<?php
// Reset a few variables
$rss_channel = array();
$item_counter = 0;

$xml_parser = xml_parser_create();
xml_set_element_handler($xml_parser, 'startElement', 'endElement');
xml_set_character_data_handler($xml_parser, 'characterData');
if (!( $fp = fopen($file, 'r') )) {
exit('Unable to open XML file.');
}

while ($data = fread($fp, 4096)) {
if (!xml_parse($xml_parser, $data, feof($fp))) {
exit(sprintf( 'XML error: %s at line %d', xml_error_string(xml_get_error_code($xml_parser)), xml_get_current_line_number($xml_parser) ));
}
}
xml_parser_free($xml_parser);

// Output as XHTML
?>
<?php
if (isset($rss_channel['ITEMS'])) {
if (count($rss_channel['ITEMS']) > 0) {
$feeds_amount = ($feeds_amount == NULL) ? count($rss_channel['ITEMS']) : $feeds_amount;

$random_entries = array_rand($rss_channel['ITEMS'],$feeds_amount); // Random array values

for ($y = 0; $y < count($random_entries); $y++) {
$entry = (is_array($random_entries)) ? $random_entries[$y] : $random_entries;
if (isset($rss_channel['ITEMS'][$entry]['LINK'])) {
?>
<div class="link"><a href="<?php echo $rss_channel['ITEMS'][$entry]['LINK']; ?>" target="_blank"><?php echo $rss_channel['ITEMS'][$entry]['TITLE']; ?></a></div>
<br>
<?php
}
else {
?>
<div class="link"><?php echo $rss_channel['ITEMS'][$entry]['TITLE']; ?></div>
<?php
}
?>
<div class="description"><?php echo $rss_channel['ITEMS'][$entry]['DESCRIPTION']; ?></div>
<br>
<?php
}
}
else {
echo '<strong>This feed contains no articles.</strong>';
}
} ?>