[jQuery] Listbox values > text box

[Diddly Doo]

I've some HTML as below. I'm trying to work out a function to transfer
the values in the listbox to the text box. So, the value of the hidden
box would be 1,2,3

<select id="foo" multiple="multiple" size="6">
<option value="1">Item 1</option>
            <option value="2">Item 2</option>
            <option value="3">Item 3</option>
         </select>
<input type="text" id="foo2" />
<input type="button" id="theButton2" value="Test" />

This is what I've got so far, not quite right though.

$(function() {
        $('#theButton2').click(
                function() {
                        $.each($("option",$('#foo')),function(i,n) 
{$('#foo2').append($
(n).attr('value'))})
                }
        )
});