brehash

This plugin adds the official <a href="http://blog.twitter.com/2010/08/pushing-our-tweet-button.html" rel="nofollow ugc">Tweet Button</a> from Twitter to your Pages, Posts or Home Page. 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.
This plugin is very customizable via ‘rsh-Tweet Button’ under the ‘Settings’ menu in WordPress Admin. Change the look and feel, pozition and where to seen of the button.

rsh-Tweet

Adds the official Tweet Button from Twitter.com.

David

This plugin shows social icons on your website. Simply put the URL in the widget area. You can also choose between different styles to customize your social icons.

Social Media Sidebar Icons

This plugin gives the opportunity to show social icons on your website. Simply drag the widget in the widget area and enter the URL of your channels.

rsh-Tweet vs Social Media Sidebar Icons