This website will give you help:
http://www.raisingbutterflies.org/eastern-black-swallowtail/

If you want to provide them protection outside, look at this thread:
http://forums.gardenweb.com/forums/load/butterfly/msg0911283324092.html?15

If they are big and fat, they will be pupating soon. The chrysalises should be kept outside or in an unheated building. The butterflies will emerge next year, probably June.

KC

Thanks! They ARE big and fat! I will keep them outside and see what happens.

Just be sure to protect them, they are primo bird food! If I can't bring them in, I place a pop-up hamper over the entire plant, keeps wasps and birds away, but doesn't do much about the spiders... or make a pull string pouch out of netting material (like for a bridal veil) and place around the branch the cat is on, just make sure there is enough room for the cat to pupate properly and emerge so the wings can expand. Good luck!

Mechelle