
Microsoft has been killing off the Zune software and replacing it with a new application. The Windows 8 Companion App for Windows Phone 8 is meant to provide users with the possibility to easily sync files between their PCs and Windows Phone 8 devices.
A Metro style app will be available from the Windows Store, is designed to replace the Zune client for Windows 8 users. The app will be automatically installed for Windows Phone 8 users on a Windows 8 PC when a device is connected. Windows 7 users will be directed to an equivalent desktop app to manage devices. The application, which will likely be branded as a "companion app," will provide quick access to photos, documents, music, and video on Windows Phone devices - allowing users to import or export data to handsets.
Source