Can not find development console

On Page: http://unity3d.com/unity/whats-new/unity-4.0

In - Other Features
I can see following:

Added a new development console to show error messages on screen in development player builds.

Haw can I find it!

Click on “development build” in the build settings. (Note that Debug.Log messages aren’t shown, only error messages, though you can use Debug.LogError.)

If Application.RegisterLogCallback ( … ); has been used then all log goes to custom logger and DevelopmentConsole do not appear.