The National Association for Interpretation is a non-profit organization that trains and supports professional and amateur interpreters in natural and cultural history. Their training covers reseach, thematic lesson planning and presentation. Many of my volunteers talk about these points in planning meetings but none of them seem to have a come basis of training so it is hard to know if the word they are using have the same meaning to each person.
This could also be integrated into the Venture Leader Skills Course, National Youth Leader Training and Woodbadge. There is a cost associated with the certification course but with a national partnership that cost should amount to the materials needed to acheive the certification.
www.interpnet.org