You can grant or deny mailbox permissions to a mailbox-enabled
user, or mail-enabled user or group, that enables or disables them
from having access to someone else's mailbox.
To grant or deny permissions to another's mailbox:
On the Start menu, point to
Programs, point to Administrative Tools, and then
click Active Directory Users and Computers.
In Active Directory Users and Computers, on the
View menu, click Advanced Features.
In the console tree, expand the Windows 2000 domain.
Double-click Users, or double-click the node that contains
the recipient information you want to modify.
In the details pane, double-click the user or group for whom
you are granting or denying permissions.
On the Exchange Advanced tab, click Mailbox
Rights.
On the Mailbox Rights tab, in Name, select a user
or group.
In Permissions, select the Allow or Deny
check boxes for the appropriate mailbox permissions.