If you missed the earlier announcement, read here.
The downtime should be about an hour, but could be all night if something goes terribly wrong. When you visit livejournal.com you'll see a message explaining the current status. customview.cgi will return some info in an HTML comment so it won't make your embedded journals ugly.
I think a party somewhere in downtown Seattle is in order for after the move.... watch news later if that happens.
Update (10:15 pm): We're still putting the rails on. Well, evan, chuck and sherm are. I'm on the floor on my laptop testing our net connection. Seems to work. :-P We probably won't start moving servers for another hour or so. This is a pain.