Formating the date picker date

Formating the date picker date

Mu date picker works, however I am not able to format the date and make the calendar smaller. Also the calendar comes on when I load the page. I am very new to this. I am not sure where to put this:
 
    $('.selector').datepicker({ dateFormat: 'yy-mm-dd' });
 
thank YOu.

 <link type="text/css" href="date_picker/development-bundle/themes/redmond/ui.all.css" rel="stylesheet" />
 <script type="text/javascript" src="date_picker/js/jquery-1.3.2.js"></script>
 <script type="text/javascript" src="date_picker/development-bundle/ui/ui.core.js"></script>
 <script type="text/javascript" src="date_picker/development-bundle/ui/ui.datepicker.js"></script>
 <script type="text/javascript"> $(function() {
                 $("#datepicker").datepicker();
     });
    </script>