Personally, I think the best website for any animal is Petfinder.com

But here is my contribution:

Helping Paws - Colchester, CT

http://www.listnow.com/helpingpaws/

Catales - Middletown, CT

http://www.petfinder.org/shelters/CT104.html

I volunteered with both Catales and Helping Paws. They are wonderful organizations and I highly recommend them both!