Kishore

This plugin is using Google Pagerank API to fetch the Google Pagerank of any webpage and the pages of your blog Features
<ol>
<li>Display page rank of you blog</li>
<li>Give your visitors a tool to check pagerank</li>
<li>Simple installation</li>
<li>Ajax based Pagerank checker</li>
</ol>

Kish PR

A plugin to check Pagerank of any website or webpage. Display pagerank of your blog pages

westondeboer

My first public plugin that shows your websites google pagerank in the dashboard. Can be disabled in the screen options menu and moved around at will.
Works 2.7+, I don’t know if it works on anything below that.
Just really an example of how to put something into the dashboard.

Dashboard Google Page Rank

This plugin shows your websites google page rank

Kish PR vs Dashboard Google Page Rank