Aşağıdaki kodu kendine göre düzenlersen sorunsuz çalışacaktır. limit 30 ayarlı istersen değişirsin.
<?php    
include('baglan.php');
$bugun = date("r");
header('Content-type: text/xml');
$cikti.="<?xml version=\"1.0\" encoding=\"iso-8859-9\"?>\n
<rss version=\"2.0\"
    xmlns:content=\"http://purl.org/rss/1.0/modules/content/\"
    xmlns:wfw=\"http://wellformedweb.org/CommentAPI/\"
    xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
    xmlns:atom=\"http://www.w3.org/2005/Atom\"
    >\n
<channel>\n
    <title>Site Title</title>\n
    <atom:link href=\"http://www.www.domainadi.com/rss.php\" rel=\"self\" type=\"application/rss+xml\" />\n
    <link>http://www.domainadi.com</link>\n
    <description>Site Açıkalamsı.</description>\n
    <pubDate>".$bugun."</pubDate>\n
    <generator>http://www.domainadi.com</generator>\n
    <language>tr</language>\n";
$sonhaber = mysql_query("select * from haberler order by id desc limit 30");
while($son = mysql_fetch_array($sonhaber)){ 
$cikti .= "\n
    <item>
        <link>http://www.domainadi.com/haberdatey.php?id=".$son['id']."</link>\n
        <pubDate>".$son['tarih']."</pubDate>\n
        <title><![CDATA[".$son[baslik]."]]></title>\n
        <description><![CDATA[".$son['detay']."]]></description>\n
    </item>\n";
}
$cikti.="</channel></rss>";
echo $cikti;
?>