Anyone can join AHNA... there is a special rate for student nurses, LVN's are welcome as well!
There are Master's programs available at New Rochelle and Colorado Springs (both of which lead to clinical specialities in holistic nursing)... I think several others have sprung up as well but I don't have the locations.
Certification as a holistic nurse is targeted to BSN-prepared RN's because of the philosophic base required. More info can be found at http://www.ahna.org/edu/certification.html
It does not take an advanced degree to certify! There are many courses across the country that qualify for the 48 hours required, and AHNA has a marvelous national conference each year in June (next year in Phoenix AZ) that will add hours.
It's a great life... great association!
Writer, HNC (Holistic Nurse-Certified) and life member of AHNA