Magento: Add Google +1 Button

# phtml
edit 
./app/design/frontend/default/default/template/catalog/product/view.phtml
add to end of "add-to-box" div
 
<div class="add-to-box">
    ...
    <!-- add google plus one button -->
    <div class="plusone-button">
        <script type="text/javascript" src="http://apis.google.com/js/plusone.js"></script>
        <g:plusone></g:plusone>
    </div>
</div>
 
# css
add
.plusone-button {
    padding: 180px 0 0;
}
 
# Links
https://developers.google.com/+/plugins/+1button/
http://www.aaronpeters.nl/blog/google-plus1-button-performance-review