Try this:
requires:
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript" src="http://malsup.github.com/jquery.corner.js"></script>
Javascript:
$('.box').corner();
HTML:
<div class="box">Hello</div>
CSS:
box{
width:150px;
height:28px;
padding:10px;
}
more examples:
http://jquery.malsup.com/corner/