tu peux tenter un truc du genre :
<?php
header('Content-Type: application/rss+xml');
printf("%s\n", '<?xml version="1.0" encoding="iso-8859-1" ?>');
printf("%s\n", '<rss version="2.0">');
printf("<channel>\n");
printf("<title>%s</title>\n", "Titre");
printf("<link>%s</link>\n", "http://adresse de ton site");
printf("<description>%s</description>\n", "description du site");
printf("\t<pubDate>%s</pubDate>\n\n", htmlspecialchars(date(DATE_RFC822)));
include ('auth.php');
if (isset($_REQUEST['nb'])){
$nb = $_REQUEST['nb'];
}else{
$nb = 5;
}
$sql = "SELECT * FROM news";
$resultat = mysql_query($sql, $id_link);
$nb = min(mysql_num_rows($resultat), $nb);
mysql_free_result($resultat);
$sql = "SELECT * FROM news ORDER BY news_id DESC LIMIT ".$nb;
$result = mysql_query($sql, $id_link);
while ($rang = @mysql_fetch_array($result, MYSQL_BOTH)) {
$titre = htmlspecialchars(strip_tags(html_entity_decode($rang['news_titre'])),ENT_QUOTES);
$desc = date("Y-m-d : ",$rang['news_date']).str_replace('/[\r\n]/g', "", htmlspecialchars(html_entity_decode($rang['news_message']), ENT_QUOTES));
printf("<item>\n");
printf("\t<title>%s</title>\n", $titre);
printf("\t<link>http://adresse de ton site</link>\n");
printf("\t<description>%s</description>\n", $desc);
printf("\t<pubDate>%s</pubDate>\n", date(DATE_RFC822,$rang['news_date']));
printf("</item>\n\n");
}
mysql_free_result($result);
printf("%s\n%s\n", "</channel>","</rss>");
?>
