Shrtnr is a project mainly written in PHP and JAVASCRIPT, it's free.
A Wordpress plugin to shorten URLs for your domain
Shrtnr is a Wordpress plugin. It's designed to shorten URLs, think bit.ly or tinyurl.com, but specifically for your domain. You can choose to overwrite the auto-generated URL structure with your own, hopefully, more easily rememberable path.
For example say you've written an informative blog post on Node.js. Instead of having a short url like
http://yrdoma.in/x7sW9
You might want to use
http://yrdoma.in/node
This is a work in progress, i.e. it isn't an officially released plugin yet, so don't come sue me if your blog about cats blows up. Sorry in advance.