Du måste skapa nya tabellrader (<tr>) för varje rad du vill ha. Just nu skapar du bara upp tabellceller.
function listCustomers(){
?>
<table border="1" name="lstCustomers" style="width: 900px;">
<tbody>
<tr>
<td style="width: 380px; text-align: center; vertical-align: middle;">Kund
</td>
<td style="text-align: center; vertical-align: middle;">Redigera
</td>
</tr>
<?
$sql="SELECT Kund_ID, Kundnr, Namn FROM tblKund ORDER BY Kundnr";
$res=ask_db($sql);
while($row=mysql_fetch_array($res)){
print "<tr>";
print "<td style=\"text-align: left; vertical-align: middle;\">" . $row['Kundnr'] . "-" . $row['Namn'] . "</td>";
print "<td style=\"text-align: center; vertical-align: middle;\"><a href=\"customers.php?action=1&CID=" . $row['Kund_ID'] . "\">Redigera</a>\n</td>";
print "</tr>";
}
?>
</tbody>
</table>
<?
}