viperchill

ViperBar adds an attractive bar to your site header, which you can use to increase blog or newsletter subscribers. It includes built in styling, Aweber & Feedburner integration, conversion rate tracking, split-testing, themes, and much more.
<a href="http://www.viperchill.com/" rel="nofollow ugc">ViperChill</a>, a blog on Viral Marketing, is the creator of this plugin. If you want to take your blog to the next level, you should read this post on <a href="http://www.viperchill.com/wordpress-seo/" rel="nofollow ugc">WordPress SEO</a>.
<h3>Donations</h3>
You may make donations at http://www.viperchill.com

ViperBar

ViperBar adds an attractive bar to your site header, which you can use to increase blog or newsletter subscribers.

Shrinivas

Super Share wordpress social plugin by MasterBlogster shows the social sharing buttons in a popup box only when reader reaches the end of the article. It also contains a Feedburner subscription form.
Here is the <a href="http://masterblogster.com" rel="nofollow ugc">live demo of Master Blogster Super Share plugin</a>
Plugin homepage: http://masterblogster.com/plugins/super-share-wordpress-plugin
 [It is highly recommended to update the plugin to the latest version i.e. 1.1]

Super Share

Super Share wordpress social plugin by MasterBlogster shows the social sharing buttons in a popup box only when reader reaches the end of the article.

ViperBar vs Super Share