Global Admin Access to Users:

Some times we need to give Full Control to the Specific Users to access all the site collections in the Farm. At that time it is not Possible to go to each and every sitecollections and give Full Control to all the site Collections.

Moss 2007 Provides the Option Called Policy for the Web application where we can add the user to access all the Site Collections with specific Permissions.

Steps:

Central Administration-->application management-->under application Security Tab-->Policy for the Web application->Add Users -->Need to select the Zones-->Next-->