Puoi fare cosi....

File : test2067a.php
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function add() {
 aTable = document.getElementById('table1');
 newRow = aTable.insertRow(-1);
 newCell = newRow.insertCell(-1);
 newCell.innerHTML = 'Commento<input type="text" name="pippo[]" size="30">';
}
//-->
</script>

</head>
<body>
<form action="test2067b.php" method="post">
<input type="button" value="add" onclick="add()">

<table id="table1">
</table>
<HR>
<input type="submit" value="Invio" >

</body>
</html>

File : test2067b.php
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>
</head>
<body>
<? 
$pippo = $HTTP_POST_VARS['pippo'];
foreach ($pippo as $value) {
 print "$value
";
}

?>
</body>
</html>