Digg today officially launched a Firefox 3 extension that creates a toolbar in Firefox 3, and while you browse the web, you can submit stories to Digg directly using the toolbar. If the page you are visiting is already dugg, then it will show number of diggs and comments and will let you digg the story.

Another useful feature of this extension is the Notifications. Whenever a story gets popular on digg, it’ll show you a notification on the bottom right corner. You can select the topics for which you want to recieve notifications through Settings.

Here is a quick screen cast of using Firefox 3 Digg extension by Digg creator Kevin Rose.

Get the Digg firefox 3 extension here.