Allan Collins

Ever wanted to see your FeedBurner stats on the WordPress Dashboard? Well now you can with this simple plugin. The plugin uses FeedBurner’s Awareness API to get your feed subscriber stats directly from FeedBurner. So now you can easily check your subscriber stats from the WordPress Administration section.
-Graphing of stats from 01-01-2008 to the present.
<h3>Sidebar Widget</h3>
If you have a widget ready dynamic sidebar, you can add the FSS Widget.
Add this code: [fss_subscribers] to view the subscriber count.
You can customize how this looks for example:
There are [fss_subscribers] subscribers to this blog.
WILL DISPLAY:
There are 20 subscribers to this blog.

Feed Subscriber Stats

This plugin will show the number of subscribers according to FeedBurner/Google. Important: WordPress 2.7 and up.

Md Abul Bashar

Just use Feedburner Email Subscriber service on your website sitebar widget.
Full <a href="http://www.codingbank.com/item/wp-feedburner-email-subscriber-wordpress-plugin/" rel="nofollow ugc">Documentations</a>
You can watch this videe 
https://www.youtube.com/watch?v=lqQnR_21UvQ

WP Feedburner Email Subscriber

Does the job

Just use Feedburner Email Subscriber service on your website sitebar widget..

Feed Subscriber Stats vs WP Feedburner Email Subscriber