One Click Shorten URL in Safari
If your looking for a simple and fast way to shorten URL’s in safari web browser then clint-ecker short url extension is for you.
clint-ecker short url extension will find the best possible short URL for a given web page.
It will extract a site’s preferred short url from its short URL <link> tag. If this is not available, it will defer to your preferences. By default this extension will obtain a short URL from the is.gd service. you can also input your bit.ly API credentials to use their service.
To use clint-ecker short url extension Click the 
button in your toolbar or use the keyboard shortcut i.e option+s
Screen shots :
Download Short URL Extension For Safari 5
You can direct download from here.