Microsoft have decided to change the name of Windows Server 8 to Microsoft Server 2012. The name change confirms that the new Microsoft server will be released this year and should be around the same time as Windows 8 release. Windows 8 is expected to be release sometime in October this year.
Windows Server 2012 beta is available for download right now. There should be more information as we get closer to the release date of Windows 8 and Microsoft Server 2012.