Windows Server 2008 (R2) blog by Kurt Roggen [BE]

Microsoft Windows Media Services 2008 is an industrial-strength platform for streaming live or on-demand audio and video content to clients over the Internet or an intranet.  Use Windows Media Services 2008 to configure and manage one or more Windows Media servers running on the Windows Server 2008 operating system.

The software is an optional supplement to Microsoft Windows Server 2008. In Windows Server 2008 RC1, the "Streaming Media Services" role (which includes the latest version of Windows Media Services) and remote administration tools are not included in Server Manager. To get the new features and tools available in Windows Media Services for Windows Server 2008 RC1, such as the built-in WMS Cache/Proxy plug-in, you must obtain and run the appropriate Streaming Media Services role installer file on the updated platform.

These Microsoft Update Standalone Package (MSU) files install either 32–bit (x86) or 64–bit (x64) versions of:

• Windows Media Services and the rest of the "Streaming Media Services" role in Server Manager, on “full” installations of Standard, Enterprise, Web, and Datacenter editions of Windows Server 2008 RC1.
• "Streaming Media Services" Server Core role, on Server Core installations of Standard, Enterprise, Web, and Datacenter editions of Windows Server 2008 RC1 (via OCsetup).
• Windows Media Services snap-in for Microsoft Management Console (MMC) on a computer that is running Windows Vista Business, Enterprise, or Ultimate edition.

Download here and run through the release notes.

For more information: How to install Windows Media Services 2008
Additional reading: Windows Media Services 2008 website