algo asi???:
Código PHP:
<html>
<head>
<script language="javascript" type="text/javascript">
<!--
var x=0;
function agregar(){
document.getElementById("celda").innerHTML = document.getElementById("celda").innerHTML + "<input type='text' name='input"+x+"'><br>";
x++;
}
-->
</script>
</head>
<form name="form">
<table>
<tr>
<td id="celda">
<input type="button" value="mostrar" onClick="agregar()"><br>
</td>
</tr>
</table>
<input type="submit" value="Enviar">
</form>
<body>
</body>
</html>