fiskeben

Adds a link to each post that points the user to Twitter.com. Before the redirect, the URL for the actual post is sent to Tinyurl.com and the tinyurl-ified URL is used as an argument to Twitter.com thus putting it in the status field when the page loads.

FishyTweet

Adds a "Tweet this" link to posts, shortens URLs with tr.im or TinyURL and sends the user to Twitter.com.

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.

FishyTweet vs k0nsl Short URLs