How to create a sitemap using PHP & MySQL

I use this on my site, it works well and you can point Google's webmaster tools to "this_file.php" and it works wonders!

<?php
header("Content-type: text/xml");
echo'<?xml version=\'1.0\' encoding=\'UTF-8\'?>';
echo'   <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">';

include '../include.php';
$sql = mysql_query("select blah from bleh");

while ($string = mysql_fetch_array($sql)){?>
            <url>
                <loc>http://www.domain.com/dir/<?echo $string['value'];?>/index.php</loc>
                <changefreq>weekly</changefreq>
            </url>
<?php } ?> 
</urlset>