test.html

<!DOCTYPE html>
<html>
  <head>
    <title></title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <script type="text/javascript" src="jquery-1.5.1.js"></script>
    <script type="text/javascript" src="../jquery.color.js"></script>
  </head>
  <body>
    <div id="test" style="background-color: #00ffff">Test string</div>

    <script type="text/javascript">
//<![CDATA[

      var $div = $("#test");
      $div./*animate({"background-color": "#ffff00"}, 300).*/
        animate({"background-color": 'transparent'}, 400);

//      var savedColor = $div.css("backgroundColor");
//      alert(savedColor);
//      $div.animate({"background-color": "#ffff00"}, 300).
//        animate({"background-color": savedColor}, 400);

//]]>
    </script>

  </body>
</html>