JQuery: Acessando o valor de um radio button

<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
   $(document).ready(function() {
      $("#button").click(function() {
         var vMostrar = $("input[name='teste']:checked").val();
	alert(vMostrar);
      });
   });
</script>
   <input name="teste" type="radio" value="1" />&nbsp;1
   &nbsp;&nbsp;&nbsp;&nbsp;
   <input name="teste" type="radio" value="2" />&nbsp;2
   &nbsp;&nbsp;&nbsp;&nbsp;
   <input name="teste" type="radio" value="3" />&nbsp;3
   &nbsp;&nbsp;&nbsp;&nbsp;
   <input name="teste" type="radio" value="4" />&nbsp;4

<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
   $(document).ready(function() {
      $("#button").click(function() {
         var vMostrar = $('input:radio:checked').val();
	alert(vMostrar);
      });
   });
</script>