GeekRMX

This plugin allows you to easily add Twitter @Anywhere to your blog, enabling the @Anywhere features:
<ul>
<li>Auto-linkification of @usernames</li>
<li>Hovercards</li>
<li>Follow button</li>
<li>Tweet Boxes</li>
<li>Retweet button</li>
</ul>
You can enable and configure each function from the plugin settings page:
<ul>
<li>Customize the label, content and dimensions of your Tweet Boxes.</li>
<li>Display the post title and short URL into the Tweet Box.</li>
<li>Shorten your URLs with bit.ly or is.gd.</li>
<li>Insert custom Tweet Boxes by using shortcodes.</li>
<li>Clicking the Retweet button will launch a special Tweet Box with Lightbox effect (<a href="https://wordpress.org/extend/plugins/twitter-anywhere-plus/screenshots/" rel="ugc">screenshot</a>).</li>
<li>Choose from two Twitter birds to be displayed above the Retweet Box 🙂</li>
</ul>
Languages:
<ul>
<li>English (en_US)</li>
<li>Spanish (es_ES)</li>
<li>French (fr_CA)</li>
<li>Belorussian (be_BY)</li>
</ul>
In order to use @Anywhere, you must first register your blog for a free API key with Twitter. You can do so at the following URL: http://dev.twitter.com/anywhere/apps/new (<a href="https://wordpress.org/extend/plugins/twitter-anywhere-plus/faq/" rel="ugc">FAQ</a>)
<a href="http://www.ngeeks.com" rel="nofollow ugc">nGeeks.com</a>
<h3>Translations</h3>
<ul>
<li>English (en_US) [default]</li>
<li>Spanish (es_ES)</li>
<li>French (fr_CA) – <a href="http://siliticx.ca" rel="nofollow ugc">Charles Desaulniers</a></li>
<li>Belorussian (be_BY) – <a href="http://pc.de" rel="nofollow ugc">Marcis G.</a></li>
</ul>
You can help translating the plugin into your language. 
Use the <code>tap-default.po</code> file included with the plugin.

Twitter @Anywhere Plus

This plugin allows you to easily add Twitter @Anywhere to your blog, enabling the @Anywhere features.

Pete Mall

This plugins enables you to add the official <a href="http://blog.twitter.com/2010/08/pushing-our-tweet-button.html" rel="nofollow ugc">Tweet Button</a> from Twitter. It lets your users share links directly from the page they’re on. When they click on the Tweet Button, a Tweet box will appear — pre-populated with a shortened link that points to the item that they’re sharing.

WP Tweet

Adds the official Tweet Button from Twitter.

Twitter @Anywhere Plus vs WP Tweet