Das Bookmark Tool von AddThis find ich ganz brauchbar:

Bookmark 

<!-- AddThis Button -->
<div class="addthis_toolbox addthis_default_style">
<a href="http://addthis.com/bookmark.php?v=250&amp;username=xa-4b4494033d98d9e1" class="addthis_button_compact">Bookmark</a>
</div>
<script type="text/javascript" src="http://s7.addthis.com/js/250/addthis_widget.js#username=xa-4b4494033d98d9e1"></script>