Windows Server "Longhorn" is the codename for the next server operating system from Microsoft. It will be the successor to Windows Server 2003, and will be called Windows Server 2008 - it is known that Microsoft intend to keep the yeat based naming scheme for its server products. According to Bob Muglia, senior vice president of servers and tools at Microsoft, the current release timeframe for Server "Longhorn" is the second half of 2007.
Server "Longhorn" will be the server equivalent of Windows Vista (previously also known by the codename "Longhorn"), and is likely to contain many of the same features, as well as others aimed specifically at high-end users. This is a similar relationship to that between Windows XP and Windows Server 2003 (codenamed "Whistler" and "Whistler Server", respectively).
Beta 1 of Longhorn Server was released on July 27, 2005. Beta 2 was announced and released May 23, 2006 at WinHEC 2006, and Microsoft intends on releasing a feature-complete Beta 3 to the public in the first half 2007.
