gentlesource

This plugin creates a short URL from the blog post permalink and stores it 
in the database. The URL is displayed below the blog post along with a link 
to twitter that passes the short URL on.
You can use all short URL services that offer an API. Here are a few:
<ul>
<li>http://melt.li/</li>
<li>http://lin.io/</li>
<li>http://unrelo.com/</li>
<li>http://bit.ly/</li>
<li>http://u.nu/</li>
<li>http://tinyurl.com/</li>
</ul>

GentleSource Short URL

Automatically shortens the blog post URL.

netandreus

This plugin adds ability to create short URL from the blog post permalink and stores it in the database. The plugin currently use tok.pw as the only service and stores the data in the database of tok.pw.
Plugin homepage: http://tokarchuk.ru/2013/03/tok-pw/
For support use WordPress.org or this page: http://tokarchuk.ru/2013/03/tok-pw/
Thanks!

tokpw Short URLs

Automatically shortens the blog post URL via tok.pw.

GentleSource Short URL vs tokpw Short URLs