cavimaster

Simple whois tool in a widget
Post a domain name et submit. 
Whois on widget return to you a complet whois query into Jquery lightbox. 
You can use shortcode like: [WHOIS] for put it in your page or post.
<a href="http://www.devsector.ch/cavimaster/category/developpement/wordpress-plugins-widgets" rel="nofollow ugc">Cavimaster_blog</a>
Original PHP whois code by Sven Cailteux – <a href="http://www.dimension-internet.com" rel="nofollow ugc">Dimension internet</a>

Whois on widget

FasterThemes

Quick Whois WordPress Plugin Shows whois information of the provided domain name. You can use Widget in the sidebar or you can also use Shortcode in the pages/posts.
<a href="http://whois.fasterthemes.com/" rel="nofollow ugc">DEMO of Quick Whois plugin</a>
Features:
<ul>
<li>You can use this plugin in your sidebar by dragging and dropping “Quick Whois” Widget.</li>
<li>You can use this in any specific page/post by putting shortcode [quick_whois].</li>
<li>This plugin converts your website into a whois data provider website in a few seconds !</li>
</ul>
<h3>License and Copyrights for Resources used in this plugin</h3>
i) We have used phpwhois.org php script from this website http://www.phpwhois.org Copyright which is a free software and we are allowed to redistribute it and/or 
modify it under the terms of the GNU General Public License v2.
<pre><code>For any help you can mail us at support[at]fasterthemes.com
</code></pre>

Quick Whois

Quick Whois Plugin Shows Whois information of the provided domain name.  You can do this using Widget/Shortcode.

Whois on widget vs Quick Whois