Last week, Windows 8 user interface screenshots hinting Metro UI inspiration were leaked. Microsoft had released the Windows 8 Milestone 3 build to limited number of hardware partners. Rafael Rivera, Windows Hacker and Paul Thurrott, Windows IT Pro editor, got their hands on some exclusive images of the Window 8 pre-beta builds and posted an image of Windows 8 Welcome Screen and also the Windows Explorer that sports the Ribbon User Interface used so far in Office products and MS Paint.
Rafael and Paul have released the Welcome Screen image and also couple of screenshots showing the usage of Ribbon UI in the native Windows Explorer. The Welcome Screen of Windows 8 clearly carries the Metro UI of Windows Phone 7 typography. Check out the screenshot below.

Windows 8 Logon Screen (Welcome Screen)
In Windows 7, you can already see the Ribbon UI implement in Paint and Wordpad. Microsoft wil be implementing the same Ribbon UI to the Windows Explorer along with other handy features. For instance, you ll also get the Sync and Web Sharing options to upload the data to the cloud services like Skydrive and others.

Windows 8: Windows Explorer new Ribbon UI
Microsoft would be adding web-elements at every possible place in the Windows 8 and let users choose an option to sync and store data on Microsoft s cloud servers. It s quite unsure whether all features would be implemented and available to all versions of Windows 8 (read Stock Keeping Units). Just like Windows 7 Starter is like Vanilla version without Windows Aero effect et al, Microsoft might but offering this feature only in certain SKUs like Windows 8 Ultimate or something.
Rivera also pointed out that the Ribbon UI in the Explorer would be having an expansive file menu. Take a look at the screenshot below to see how Ribbon UI will look in the Windows Explorer.

Windows 8 Ribbon UI: Consolidated File Menu (see "View" button at the bottom-right

Windows 8: Windows Explorer new Ribbon UI

3 Windows 8: Library Tools - Dynamic Ribbon

4. Windows 8: Library Tools and Picture Tools - Dynamic Ribbons

5. Windows 8 Ribbon UI: View button in Details Pane