Step 1

In Add the following line of code to your includes/templates/common/html_header.php 
directly following <?php } //endif FAVICON ?>

<script type="text/javascript" src="https://apis.google.com/js/plusone.js"></script>

Step 2

Then, in your product pages (this is really the best place for them) add the 
following, styled however you like.

<g:plusone size="tall"></g:plusone> <a title="Post to Google Buzz" class="google-buzz-button" href="http://www.google.com/buzz/post" data-button-style="normal-count"></a><script type="text/javascript" src="http://www.google.com/buzz/api/button.js"></script> <a href="http://twitter.com/share" class="twitter-share-button" data-count="vertical">Tweet</a><script type="text/javascript" src="http://platform.twitter.com/widgets.js"></script> <script src="http://connect.facebook.net/en_US/all.js#xfbml=1"></script><fb:like layout="box_count" font="verdana"></fb:like> <script src="http://www.stumbleupon.com/hostedbadge.php?s=5"></script></span>

That's it... Socially up to speed.