codice:
$num=1;
$flag=false;
echo "<table><tr><td>\n";
echo "<table>\n"; 
$temp=ceil($totalRows_musei_lista/2);
while ($row_musei_lista = mysql_fetch_assoc($musei_lista)){
	if ($num > $temp && $flag == false){
		$flag=true;
		echo "</table></td><td><table><tr>\n";
	}
	echo"<tr><td class=\"corpo\">{$row_musei_lista['ID']}</td></tr>\n";
	$num++;
}
if ($num % 2 == 0)
	echo"<tr><td class=\"corpo\"></td></tr>\n";
echo "</tr></table>\n";  
echo "</td></tr><table>\n";