Enterprise-wide Permissions

Hi All,
Is there anyone that knows whether it is possible to have one administrative account to manage the resources in an enterprise that consists of two domains residing in two different forests.e.g
domain A and Domain B. Domain A belongs to one forest and B in another.If i create an administrator account in domain A,how can i permit this account to log on to any computer in the enterprise(including the domain controllers in domain b)Your help will be highly appreciated.
Both domains are running on Windows 2000 Advanced Server operating systems.