Very simple, very useful, works perfectly Rated 5 out of 5 stars

Works perfectly using a very well-established URL shortening service. Just have to get your API key after signing up at bit.ly - it's at http://bit.ly/a/your_api_key in case you can't find it ;)

Only bad thing is the really ugly icons - sorry, they're just plain horrid! Luckily, you don't need to use any of them (everything's possible with a simple right-click on the page whose URL you want to shorten or directly on the hyperlink you want to shorten), but it'd still be nice to be able to configure the icons :)

Also, if you could have an in-address bar icon such as the addon for spedr.com gives you, that would make it the best URL shortener on the planet :)

This review is for a previous version of the add-on (0.56).