Migrating and Restructuring Active Directory Domains, Active Directory Migration Tool (ADMT) provides a toolset to facilitate migration and restructuring tasks in an Active Directory Domain Services infrastructure.
As part of deploying the Active Directory directory service or Active Directory Domain Services (AD DS), you might choose to restructure your environment for the following reasons:
1. To optimize the arrangement of elements within the logical Active Directory structure
2. To assist in completing a business merger, acquisition, or divestiture

The name ADMT stands for Active Directory Migration Tool.You can use ADMT to migrate users, groups, and computers between AD DS domains in different forests (inter-forest migration) or between AD DS domains in the same forest (intra-forest migration).
ADMT can also perform security translation (to migrate local user profiles) when performing inter-forest migrations.

System Requirements
1. Supported Operating Systems: Windows Server 2003; Windows Server 2003 Service Pack 1; Windows Server 2003, Datacenter x64 Edition; Windows Server 2003, Enterprise x64 Edition; Windows Server 2003, Standard x64 Edition; Windows Small Business Server 2003
2. ADMT can be installed on any computer capable of running the Windows Server 2003 operating system.
3. Target domain: The target domain must be running either Windows 2000 Server or Windows Server 2003
4. Source domain: The source domain must be running Windows 2000 Server, Windows Server 2003, or Windows NT Server 4.0
5. The primary domain controller (PDC) of a Windows NT Server 4.0 source domain must have SP4 or higher installed.
6. The ADMT agent (installed by ADMT on the source computers) can operate on computers running Windows NT Server 4.0 (with SP4 or higher); Windows 2000 Professional, Windows 2000 Server, Windows XP, and Windows Server 2003.

The license of this software is Freeware, you can free download and free use this server utility software.