Julio Potier

AutoShortener can create short links in your WordPress website for your posts and pages but also for external links. 
You got many many great options, a usefull admin panel, bookmarklets, shorcodes. 
But easy to use ! Visit website www.autoshort.com for more informations.

BAW AutoShortener

AutoShortener can create short links in your WordPress website for your posts and pages but also for external links.

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.

BAW AutoShortener vs k0nsl Short URLs