$r = 0;
echo "<table><tr>";
$sorbakalim=mysql_query("select * from tablo");
while($yazbakalim=mysql_fetch_array($sorbakalim)){
$r++;
?>
<td width="15%" bgcolor="<?=$tableborder?>" class="baslik_beyaz21"><center><a href="urungoster.php?id=<?=$id?>"><?=$markaadi?> <?=$urunadi?></a> <img src="img/yeni.gif" alt="yeni" width="50" height="12" /><br><img src="Upload/galeri/<?=$resim?>"/><br><?=$tanitim?></center>
<?
if ($r % 2 == 0 )
{
echo "</tr><tr>";
$r=0;
}
}

echo "</tr></table>";
?>