As the hurrincanes of 2005 (Katrina) and 2008 (Ike) demonstrated, animals aren't generally at the top of the list of what to bring when some people evacuate. In the case of larger animals, such as horses and cows, they generally can't be moved to a safe location but are instead, left to fend for themselves.
If you are considering taking an animal into your home, I would ask that you adopt one from a local animal shelter and avoid, at all costs, puppy and kitten mills. There are millions of animals across the country waiting to be adopted who would make a wonderful pet without having to resort to people whose only goal is to produce more animals. Once you have adopted an animal, be sure, as Bob Barker would say, to spay or neuter your pet.
If you know of a site which should be included, please let me know.