Plenty of questions out there for mailbox moves from Exchange 2003 to Exchange 2007/2010, but I'm curious about the following:
What do users experience in Outlook 2010 while their mailbox is moved between Exchange 2003 servers in the same forest?
Are they able to access their mailboxes, and send/receive mail?
As far as I remember (haven't done this since the release of Exchange 2007), the users whose mailbox is currently being moved won't be able to send / receive mails, but won't notice it (e.g. outlook doesn't behave differently). After the move is completed, every mail sent or received will be delivered. You could say the migration is "transparent" for the users.
(Maybe Outlook 2010 will even show the "your mailbox is being moved" tooltip, but I'm not sure)
Edit: but as always, it's good practice to schedule such a thing for the low-peak hours of your business.
