It is always a much better experience for everyone if the migration is understood on paper before the actual event takes place. To this end, I would recommend reading through the migration steps in these chapters and then going back to the beginning of these steps to further evaluate the impact upon the users.
There will be moments of down time as the server is rebooting and the network is reconfiguring, and while files, data, users, and settings are moved between systems. It is not possible for me to put an actual time on this as it all depends on how much data there is to move. My first migration took me 5 days, spread over two weekends, while my second migration took a little over a day.
If you have a vanilla SBS 2003 system then all stages will be very simple, but if you have a number of line-of-business applications then you will also need to plan on how to move these.
I can't provide guidance on these applications, but they normally consist...