Astro-tourism has been promoted widely by many international astronomy organisations over the past few years.
The two main institutions which regulate and certify any dark sky region in the world are the International Dark Sky Association and Starlight Foundation. They list the accredited dark sky regions as well as technical information on reducing light pollution.
The Office of Astronomy for Development (OAD) of the IAU has astro-tourism as one if its flagship projects as well, and focuses on the socio-economic developmental aspects of astro-tourism. See here and here.