Migration Toolkit is the strategic offering from Microsoft that
assists you in solving technical and business problems pertaining to
restructuring of your Active Directory environments, as well as
transitioning from NT4.0 to Active Directory. ADMTv3 enhances the rich
feature set of v2 with a new backend database, support for simultaneous
migration tasks, multiple ADMT consoles with delegation, agent
enhancements, full object rename, and a host of other improvements.