It looks as if Twitter will be rolling out their new URL shortner service this summer. It is currently being tested with Twitter employee accounts and will take the structure of http://t.co. Twitter is currently integrating their own URL shortner (http://twt.tl) within Direct Messages (see Twitter Quietly Rolls Out Own URL Shortner). Twitter also goes on to state that there will be some sort of integration within the interface to automatically covert long URLs to http://t.co/ URLs. This has been a wanted feature for a very long time as users had to use a third-party URL shortner and copy and paste the link into the status update form. They also mentioned that third-party apps will be able to use this URL shortening service. Not sure if all links from these third-party apps will be automatically converted.
With the roll out of this URL shortening service, I believe that this is one step closer for Twitter to provide analytic link data to the user. So my guess would be that we will be seeing some sort of stats dashboard in the near future.
For those technical folks - you will want to stay away from shortening a short URL (i.e bit.ly to t.co). This will cause a "chain redirect", which Google frowns upon. If you shorten a link like bit.ly you are now producing a 301 redirect from t.co to bit.ly. The bit.ly URL will produce a 301 redirect to the original URL, thus causing a "chain redirect".