Active Directory has an Employee-ID attribute for user objects but unfortunately this attribute is not exposed in UI (i.e. in Active Directory Users and Computers) so you can't easily configure it if you want to use it. You can of course configure this attribute of a user account using one of the command-line tools for managing Active Directory such as LDIFDE or DSMOD, and you could also use ADSIEdit or even ADSI scripts to configure it. What you may not be aware of however is that you can programmatically extend ADUC to expose this attribute in the UI. To learn how to do this, download the ADSI SDK and install it and look in the Samples\DSUI\userext\userproppage where you can learn how to create an extension for employee ID and thumbnail photo.
Mitch Tulloch is 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. Mitch is also the author of Introducing Windows Server 2008, the first book from Microsoft Press about the exciting new server platform. For more information on these and other books written by Mitch, see www.mtit.com.