Quote Originally Posted by MMemmer View Post
In addition when making the move I would recommend allowing for a few days while DNS propagates and to verify that new hosting is working as planned before the old account is taken down.
Mark and everyone are right on the money..

Migration is all dependent on how your new host handles the process and DNS cutover is the biggest 'gotcha'.
Most good hosts will have options and expertise to minimize the downtime, with static pages, replication, etc.
Moving to a new server makes it very easy...