Código HTML:
$(function(){
$("#select_all").click ( function(){
$("#frm1 input[type='text'].child").attr ( "" , $(this).attr("" ) );
});
});
<form id="frm1">
<table>
<tr>
<td>
<input type="text" id="select_all" />
</td>
</tr>
<tr>
<td>
<input type="text" name="select[]" class="child" />
</td>
</tr>
<tr>
<td>
<input type="text" name="select[]" class="child" />
</td>
</tr>
<tr>
<td>
<input type="text" name="select[]" class="child" />
</td>
</tr>
</table>
</form>