I have a client that I host a pretty large scale web application for in our data center. We recently changed ISPs and will need to change the IP address for the primary web server on Saturday morning. My concern is, that this application is used by clients all over the world and I've heard horror stories about DNS changes taking several days to propagate to caching international name servers. I need the application to be down for the 30 minutes that I move the server from one cage to another and then for it to come back up as quickly as possible. Even internationally.
Anything I can do NOW to ensure that the international clients will be able to access the system remotely after the change?