I’ve used the shortener myself and it’s an excellent service. No ads, no frames, no fuss. Just enter the URL you want to shorten, an optional custom keyword, and click on the ‘Shorten It!’ button.
Almost instantly, a new page loads with your shortened URL in an input field for easy copying to the clipboard. Links to social networking sites are also provided for easy sharing. Click on the EasyChirp link for example, and your shortened URL will be inserted into the textfield for you on the EasyChirp page.
But wait, it gets better! Drag the bookmarklet to your browser’s toolbar and you can shorten the URL of any web page you happen to be viewing with a single click. 8-)
Strange that it hasn’t received more exposure. I get the feeling that WebAIM don’t want to shout about it too loudly in case the shortener is abused by spammers. Hence, I only quoted the shortener’s URL above, and didn’t link to it.