The International Association of Certified Home Inspectors (InterNACHI) is an excellent professional organization for home inspectors and a great source of information for consumers. 

The International Code Council (ICC) is the proponent for the International Residential Building Code used throughout the United States.  The ICC provides national training, testing and certification for Building Inspectors, Mechanical Inspectors, Electrical Inspectors, Plumbing Inspectors, Energy Conservation Inspectors, Building Officials and others.  A great site for code information.