Exchange 2007 Moving Mailboxes

When you move a mailbox, you move the data in the mailbox from one mailbox database to another. Be aware of the following when using Move-Mailbox:
You can move a mailbox to a different database on the same server, to a different server within the same forest, or to a different server in another forest. (To move a mailbox from one forest to another, you must use the Move-Mailbox cmdlet.)