As of now, we have setup Exch 2010 on a 2008 R2 64 bit server. We believe that the procedures that we took are correct which we followed the step-by-step on the link below. Now that we are up and running, we see all the users in recipient>mailboxes but cannot move any of them over. I believe there might be a trust issue of some sort because when we choose to move, we do not ever see the 2003 exch server in the list (which should be in there - even if we don't select it).
As of now we get an error that the mailbox database does not exist for the 2003 exch (the state of the database is live - not sure if I need to make it offline, if so how?).