GoHorseShow.com has been searching for an organization that is currently helping animals including horses in Japan. The organization that seems to be the most organized so far is World Vets. Check out their website and click on the Donate for Japan Disaster Relief button to help with the cause. They have also updated their relief efforts in Japan so check out their details by clicking on this link!
The focus of World Vets is to provide international veterinary assistance to impoverished nations outside of North America. World Vets is able to assist foreign animal groups, animal health care professionals, and/or communities reach their animal welfare goals.