Cat Out Loud has a worthwhile post titled, Struggling with euthanasia in the face of evacuation. She has also been dispensing other good forethoughts and advice about dealing with pets in emergencies. Obviously, Katrina is the catalyst for this thought (puns mercilessly intended).
My wife and I hope that, if there were ever any looming natural disaster requiring us to leave our home, we would be able to evacuate with our beloved cats. Leaving them defenseless in the woods of Maine is too terrible to think about. I guess instinct might get them through some of the real world's challenges, but two of them are getting up there in years. The oldest one is awful hard to catch when it's time to take a trip to the vet, though.