• USMT performs approximately the same tasks as Windows Easy Transfer. USMT migrates user settings, documents, and application configuration settings. USMT has a command-line interface and a graphical interface.
• The configuration of USMT is done by editing the XML files
• MigApp.xml: Used to include or exclude the setting for specific applications.
• MigUser.xml: Used to control which file types, user folders, and desktop settings are included in the migration.
• MigSys.xml: Used only when migrating operating system and browser settings to a Windows XP computer.
• Config.xml: A customer configuration file that allows you to control the migration process in detail.
• The following steps in the USMT migration process are:





• Use ScanState on the source computer to collect settings and files
• Install Windows 7 on the destination computer
• Use LoadState on the destination computer to import settings and files
• When ScanState is used to collect settings and files, they are stored in an intermediate location. All applications should be installed on the destination computer before LoadState is used.
• The Config.xml file is generated by running ScanState.exe with the /genconfig option. It captures all of the settings that are being migrated. You can edit this file to control which of the settings are actually migrated when ScanState.exe is run. You can use multiple Config.xml files to control the migration process in different ways for users with different needs.

Read more about the User State Migration Tool at:
http://technet.microsoft.com/en-us/library/dd560801(WS.10).aspx.