We've designed a simple API for applications wishing to to use thurly to provide shortened URLs to their users. The API allows you to submit a long URL via the thurly URL and returns a plain text page with the shortened URL.
Send thurly your long URL in a way similar to this:
http://thurly.net/api.php?id=http://www.longurl.com/goes/here
Thurly takes the web address after the ?id= and processes it, shrinking it down for your application or website. Please note that the protocal (http:// for example) is required. Thurly will end in an error without it.
You will receive your shortened URL as a plain text HTML page. The returned page will contain only your shortened URL and will not have any HTML header information.

Tweetie 2 for the iPhone and iPod Touch allows you to choose your own URL shortener. In the account settings on Tweetie choose 'URL Shortening.' One there choose 'Custom' from the bottom of the menu. A URL field will appear. Type, or paste, this URL in the field:
http://thurly.net/api.php?id=%@

There are not many errors that can take place when shortening your URLs with thurly. If an error occurs it too will be returned as a plain text HTML page.
Check to be sure your URL has a protocal (http:// for example). Also be sure the ?id= is not left blank.