Document ID Feature

Document ID from Office.Microsoft.com
http://office.microsoft.com/en-us/sharepoint-server-help/enable-and-configure-unique-document-ids-HA101790471.aspx?CTT=1

Document ID Feature from MSDN
http://msdn.microsoft.com/en-us/library/ee559302

 Document ID Feature Blog Article
http://blogs.technet.com/b/blairb/archive/2009/10/20/new-document-id-feature-in-sharepoint-2010.aspx