How to Set Up an Additional Mailbox in Outlook 2007
With Microsoft Office Outlook 2007 you can manage your mailbox and connect with other users over a network. If you have administrator privileges then you can add an additional mailbox. This can be helpful if you need to monitor a separate account's mail when you are not logged into that account.
Open Microsoft Outlook 2007 . Click on "Tools" on the top menu bar.
Click on "Account Settings". A dialog box appears.
Click on "Email", "Change" and "More Settings...".
Click on "Advanced" and "Add...". Enter the mailbox user name in the text box.
Click on "OK" button and the new mailbox will be added.