Microsoft Knowledge Base Article 223787 contains the following summary:
This article describes how Flexible Single Master Operations (FSMO)
roles are
transferred from one domain controller
to another and how
this
role can be forcefully appointed in
the event
that
the domain controller
that previously held
the
role is no
longer available.
For more information about FSMO
roles in general, please
see
the following article in
the Microsoft Knowledge Base:
197132 Windows 2000 Active Directory FSMO Roles
For additional information about the correct placement of FSMO roles, please see the following article in the Microsoft Knowledge Base:
223346 FSMO Placement and Optimization on Windows 2000 Domains