Assistance Dogs

The Assistance Dog Institute
An educational and research-oriented organization focusing on assistance dogs and their relationship with humans. ADI offers degree and certification programs, conducts research, and pairs qualified patients with service dogs through an intensive training program.
http://www.assistancedog.org

Therapy Dogs

American Kennel Club
Offers the "Canine Good Citizen Program," a training course and certification that is often used as the first step to therapy dog certification.
http://www.akc.org

Animal Friends
A Pittsburgh-based shelter, pet adoption center, and resource center offering multiple services including animal behavior training and advice, a program to encourage adoption of older animals, and "wellness" programs including therapy dog visits and a pet loss support group.
http://www.thinkingoutsidethecage.org

Bideawee
A humane organization, founded in 1903 and with locations in New York City and on Long Island, dedicated to promoting and supporting safe, loving, long-term relationships between people and companion animals.  Bideawee's programs and services include pet adoption, training, and a therapy dog program.
http://www.bideawee.org

Penny's from Heaven Foundation
A nonprofit organization based in South Texas that evaluates, tests, trains, qualifies, and assists therapy dog/handler teams.  Many of the teams are currently working with wounded soldiers returning from Afghanistan and Iraq. 
http://pennysfromheavenfoundation.org

Equestrian Therapy

North American Riding for the Handicapped Association
A non-profit organization dedicated to promoting therapeutic horseback riding, and to fostering safe, professional, ethical and therapeutic equine activities. NARHA certifies instructors in both therapeutic riding and hippotherapy.
http://www.narha.org

Tewksbury Hospital Farm
A non-profit, therapeutic and able-bodied riding center affiliated with Tewksbury Hospital in Massachusetts.
http://www.t-h-e-farm.org

Pet Care and the Human-Animal Bond

The American Society for the Prevention of Cruelty to Animals (ASPCA)
An organization primarily dedicated to preventing harm to animals, but also offering extensive information on pet care and animal behavior.
http://www.aspca.org

The Animal Medical Center
A non-profit veterinary care hospital with an interest in the human-animal bond. AMC offers comprehensive animal care, training for veterinarians, and rehabilitation and fitness programs.
http://www.amcny.org

Research Centers

Center for the Interaction of Animals and Society
University of Pennsylvania School of Veterinary Medicine
An interdisciplinary and scholarly forum for research, education and public-service programs, including the study of how animals can enhance human health.
http://www.vet.upenn.edu/Research/ResearchCenters/CenterfortheInteractionofAnimalsSociety.aspx

Research Center for Human-Animal Interaction
College of Veterinary Medicine, University of Missouri-Columbia
A research center exploring how the human animal bond impacts health in people and animals.
http://rechai.missouri.edu/main.htm

Center for Human-Animal Interaction
Virginia Commonwealth University Medical Center
A research center with interest in the benefits of pet ownership to both humans and animals.
http://www.chai.vcu.edu/about/index.html