Sysprep unattend file in Windows Server 2008

The answer file is now an XML file instead of an INF file. You should to use Windows System Image Manager to create the XML file. Windows System Image Manager is part of WAIK and can be downloaded here.
To actually use this XML file, copy it sysprep.xml to c:\windows\system32\sysprep. That is the folder on a Windows Server 2008 system where sysprep.exe is located by default. From that location, you execute the following command:

sysprep /generalize /oobe /shutdown /unattend:sysprep.xml

The system will shut down. The next time you start this system (after cloning it), it will install with the settings in the XML file. The Computer Name will be automatically generated.