I have done something stupid this week. I did not heed the letter
from my ISP that my static IP at home would be changing. Right
now, no one in the world knows how to hit my domain. Argh.
But, hopefully I'm on the right track to fixing it thanks to this FAQ item.
You have to set the TTL on your zone file to something smaller and
smaller as the cut over approaches and then start taking it back up
again.