$arr = array("1c", "2c", "3c", "4c", "5c", "6c", "7c","8c","9c","10c");
$i=0;
$kr=3; // строк
$td='';
echo '<table><tr>';
foreach ($arr as $v)
{
if (($i%$kr)==0){
echo $td;$td="</td>";
echo '<td valign="top">';
}
echo $v.'<br>';
$i++;
}
echo '<tr></table>';