twurleris an AppleScript to be used as a Quicksilver plugin. Invoke the script, give it the URL you want converted through Tweetburner, and it will put into your clipboard the twurled version, which you can paste in Twitterrific (or wherever else you want).

Download the script here.

The longer version:

• The script goes in ~/Library/Application Support/Quicksilver/Actions/
• I have it set as a trigger, so that when I invoke ctrl + opt + cmd + / it pops up with “process text…” as its action. Just paste the URL you want twurled in the third pane.
• If your clipboard does not have the twurled version, you may have network problems. The script needs to access Tweetburner’s API to perform the conversion. Of course, if you are experiencing increased network latency or Tweetburner is down/slow, it may take slightly longer. My tests were all under a second for the response, but give it two or three at most.

Hope you find this useful.

P.S. Original blog post here.