---------------------The Form ----------------------------------------------------------------------

<?php
	$siswa = mysql_query("SELECT * FROM `dbsiswa` WHERE `username` != 'ADMIN' ORDER BY `nama`");
	while($siswaResult = mysql_fetch_array($siswa, MYSQL_ASSOC))
	{
		if($siswaResult['status_pembayaran'] == 'lunas')
		{
			$lunas = 'checked="true"';
		}
		else
		{
			$lunas = '';
		}
		
	echo '<tr><td height="23">'.$siswaResult['no_registrasi'].'</td><td>'.$siswaResult['username'].'</td><td>'.$siswaResult['nama'].'</td><td align="center"><input type="checkbox" name="lunas['.$siswaResult['no_registrasi'].']" value=\"lunas\" '.$lunas." /></td></tr>\n";
	}
?>




--------------------------- The Code ------------------------------------------------
<?php
session_start();
require_once('../include/conn_db.php');

if(array_key_exists('submit', $_POST))
{
	unset($_POST['submit']);
	foreach($_POST['lunas'] as $key => $val)
	{
		echo $key;
		//$update = mysql_query("UPDATE `dbsiswa` SET `status_pembayaran` = '$val' WHERE `no_registrasi` = '$key'") or die(mysql_error());
	}
}
?>