Philip John

This plugins adds a visible link to the end of every post.
Best used in conjunction with the <a href="https://wordpress.org/extend/plugins/googl-shortlinks/" rel="ugc">Goo.gl Shortlinks</a> or <a href="https://wordpress.org/extend/plugins/bitly-shortlinks/" rel="ugc">Bit.ly Shortlinks</a> plugins.
Feature requests welcomed with open arms!

Add Shortlink to Posts

Adds a link to the shortlink for each post below the content.

k0nsl

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, if defined in the settings page. The plugin currently use knsl.net as the only service and stores the data in the database of knsl.net.
Plugin homepage: http://k0nsl.org/blog/k0nsl-short-urls-plugin/
For support use WordPress.org or devNET community forums: http://devnet-software.org/
Thanks!

k0nsl Short URLs

Automatically shortens the blog post URL via knsl.net.

Add Shortlink to Posts vs k0nsl Short URLs