Edit your feed and in Advanced Settings chose custom from the "Shorten Link through" dropdown box, add the URL shortening endpoint as http://gkurl.us/shurly/api/shorten?format=txt&longUrl=%@
Due to code changes by Twitter, Twitter for iPhone is no longer supported. Try http://m.gkurl.us
You can also use gkurl.us as a custom url shortener for Tweetdeck! In Tweetdeck's settings (Settings > Services and select Other), type or paste the following URL
http://gkurl.us/shurly/api/shorten?format=txt&longUrl=%@
Then just click Save
The firefox extension Shorten URL has added gkurl.us to its list of services.
Click Allow --> Install Now --> Restart Firefox
Once installed, go to Tools ---> Shorten Url Options ---> Under selected service, choose gkurl.us
To shorten a url, right click on the page you want to shorten and choose Shorten This page (gkurl.us)
gkurl.us is one of the supported services with URL expansion by http://long-shore.com/
Drag this link to your bookmark bar to quickly create a short URL from any page: gkurl.us