David Davis

Easily allows your blog post or page to be retweeted. Currently being used by SocialBrite and other members of the social media community.
<h4>Features</h4>
<ul>
<li>
Allows you to change the source which you retweet, e.g. ” via @yourname”
</li>
<li>
Easily installation and customization
</li>
<li>
Better integration, allowing custom titles, related accounts
</li>
<li>
Integrates with WordPress MU
</li>
</ul>
<h3>Help</h3>
Please contact at us http://dcgws.com/contact/ for any questions

TweetButton

Still a favorite

Easily allows your blog post or page to be retweeted. Currently being used by SocialBrite and other members of the social media community.

H. Peter Pfeufer

Twitter has provided a twitter and retweet button. This Plugin adds the official twitter button to your blog articles, pages, archives, categories and rss.
Features
<ul>
<li>Easy install</li>
<li>Panel for easy configuration</li>
<li>Config Button Style</li>
<li>Config Language of Button</li>
<li>Config Your Twitter Account</li>
<li>Config Tweet text</li>
<li>Config display locations (entries, pages, home page, archive, category)</li>
<li>Config position in content (before, after, both, manual choice)</li>
</ul>
Note
If you choose the position as “manual choice” you have to edit your template-file and add the following code at a position of your choice. 
 <?php if(function_exists(‘wp_twitterbutton’)) { wp_twitterbutton(); } ?>
Translations
<ul>
<li>English</li>
<li>German</li>
<li>French (by: <a href="http://www.frankoli.de/blog/" rel="nofollow ugc">Frank</a>)</li>
<li>Dutch (by: <a href="http://wpwebshop.com/" rel="nofollow ugc">Rene</a>)</li>
<li>Czech (by: <a href="http://blog.michalbernat.cz/" rel="nofollow ugc">Michal Bernat</a>)</li>
<li>Hebrew (by: <a href="http://www.sagive.co.il/" rel="nofollow ugc">Sagive</a>)</li>
<li>Hindi (by: <a href="http://outshinesolutions.com/" rel="nofollow ugc">Love Chandel</a>)</li>
</ul>

WP-Twitter Retweet Button

This plugin will install the official Twitter Button provided by Twitter to your Wordpress-Blog.

TweetButton vs WP-Twitter Retweet Button