In the above video we have Microsoft’s Avi Ben-Menahem demonstrating the Xbox Live features of Windows 8.
Xbox Live on Windows 8 will support cross-platform multiplayer and will be more open to developers than on Windows Phone 7, meaning more games will be Xbox Live enabled.
According to Ben-Menahem, Xbox Live on Windows 8 will bring "everything you know and love on Xbox 360 and Xbox Live to Windows."
Via GeekWire and Engadget.com