Windows 2000 has schema version 13
Windows 2000 with Exchange 2000 has version 17
Windows Server 2003 has version 30
Windows Server 2003 R2 has version 31
To determine your schema version on a domain controller, open Registry Editor and navigate to the Schema Version registry subkey found under HKLM\System\CurrentControlSet\Services\NTDS\Parameters.
Mitch Tulloch was lead author for the Windows Vista Resource Kit from Microsoft Press, which is THE book for IT pros who want to deploy, maintain and support Windows Vista in mid- and large-sized network environments. For more information see www.mtit.com.