<form action=index.php?go=koszyk method=POST>';
                  foreach($_SESSION['koszyk'] as $klucz =>$wartosc)
                  {
                    $pom=$klucz;
                    $pom++;
                     ..........
                            <td align=center>
                                  
                            <input type="text" name="ile" size="2" value="'.$wartosc['Ilosc'].'">
                            <input type="hidden" name="id" value="'.$pom.'" >
                            </td>
  
                            <td>
                                 <input type=submit value="OK" name="al">
                            </td>
                      .........
                  }

foreach($_SESSION['koszyk'] as $klucz =>$wartosc)
     {
        if(($_POST['ile'])!=($_POST['id']))
                $wartosc['Ilosc']=$_POST['ile'];
          
     }

[color="black"][koszyk] => Array
        (
            [0] => Array
                (
                    [id_uzytkownika] => 1
                    [Nazwa_towaru] => Logitech 910-000199 RX250
                    [Ilosc] => 1
                    [EAN-13] => 5902222000017
                    [Cena] => 39
                  )
         )