Since the transition is going to take longer than I anticipated, I took Jeremy’s advice on having both servers up at once. It’s a good thing I have five static IPs courtesy of AT&T (eight years ago I only wanted two, but they only offer one or five).
In English? It means you probably won’t notice the shift and/or there will only be a briefer period of the site being offline.
Meanwhile, if you have an iPhone and want to have an iCal account for it which would have the server act as the go-between for your iPhone and computer, instead having to synchronize them, let me know. iPod Touches? I suppose they’ll work too but they’re dependent upon WiFi access and they need the version 3 upgrade of OS.