Is GUI Editor available in current version of Unity 4?

I saw the video demonstrating new GUI system from Unite 2012.

http://video.unity3d.com/video/6943180/unite-2012-using-the-new-gui

But I cannot find this GUI Editor in current version of Unity 4. Has it already been released or not? If so then please tell me how to open this feature.

It is not done. If it were available it would have been in the release notes and in the documentation.