I just added a way to autmatically add url shortening to each post. It uses the bit.ly service and their nice widget which opens a small box into the page with the shortened url ready to be posted on twitter or other services, and shows a nice set of metadata for the post itself. Here is how it looks like:
Bit.ly metadata for a post
To add it I modified the template adding this:
at the bottom of each post single-page template (single.php) and at the bottom of each post in the main index template (index.php)