Add twitter button on product detail page in magento

<a href="http://twitter.com/share" data-count="vertical">Tweet</a>

<script type="text/javascript" src="http://platform.twitter.com/widgets.js"></script>

 

<a href="http://twitter.com/share" data-count="horizontal">Tweet</a>

<script type="text/javascript" src="http://platform.twitter.com/widgets.js"></script>

 

<a href="http://twitter.com/share" data-count="none">Tweet</a>

<script type="text/javascript" src="http://platform.twitter.com/widgets.js"></script>