Bu mantığı;

<table cellpadding="0" cellspacing="0" border="0">
<?

$say =1;
while (..){
	if ($say == '1')
		{
		echo '<tr>';
		}
	?>
	<td>sutun</td>
	<?
	$say++;
	if ($say == 3)
		{
		$say =1;
		echo '</tr>';
		}
}
?>
</table>
Bu da senin kodlar için;
<table cellpadding="0" cellspacing="0" border="0">
<?
$query = $db->write_query("
                                            SELECT author_id, name, image
                                            FROM authors
                                            ORDER BY author_order ASC
                                            LIMIT 12
                                            ");

$say =1;
while($row = $db->sql_fetcharray($query)){
	if ($say == '1')
		{
		echo '<tr>';
		}
	echo '<td>';
	$qquery = $db->read_query("
                                                SELECT article_id, title
                                                FROM articles
                                                WHERE author_id = $row[author_id]
                                                AND active = 'Y'
                                                ORDER BY date DESC
                                                LIMIT 1
                                                ");
	 $rrow = $db->sql_fetcharray($qquery);
	 if($rrow[title]){
                    $article = "<a href=\"author_article_detail.php?article_id=".$rrow[article_id]."\">".stripslashes($rrow[title])."</a>";
                    }else{
                    $article = "Henüz Yazı Eklenmemiş";
                    }
					?>
	<div class="author_box">
                    <div class="image"><img src="images/authors/th_<?=$row[image]?>" width="38" height="46" /></div>
                    <div class="text"><b class="authorName"><?php echo stripslashes($row[name]);?></b><br /><?=$article?></div>
                </div>
	<?
	echo '</td>';
	$say++;
	if ($say == 3)
		{
		$say =1;
		echo '</tr>';
		}
}
?>
</table>
Umarım iş görür.