Arizona Center for Integrative Medicine
Leader in Integrative medicine education of practitioners. Many resources and a section on how to find an integrative physician around the world.

Institute for Functional Medicine
Functional medicine addresses the underlying causes of disease, using a systems-oriented approach and engaging both patient and practitioner in a therapeutic partnership. It is an evolution in the practice of medicine that better addresses the healthcare needs of the 21st century.

If you are looking for functional medicine practitioners around the country or the world, you can look here:

Duke Integrative Medicine
Cleveland Clinic – Center for Functional Medicine
Dr. Mark Hyman
Andrew Weil, MD
Physicians Committee for Responsible Medicine
Health Action Network Society
HeartMath Institute
College of Physicians and Surgeons of British Columbia