It's really easy, all you have to do is add this littlt peice of code to your website:
Code:
<img src="http://www.finqoo.com/display_rank?site=http://www.domain.com/" border="0" alt="This is my google Rank">
Your pagerank will be added wherever you place the code on your site in the form of an image and will be always updated.
Enjoy!!