Here are the links to some of the Music Therapy organizations around the world:
American Music Therapy Association http://www.musictherapy.org/
Australian Music Therapy Association http://www.austmta.org.au/
British Association for Music Therapy http://www.bamt.org/
Canadian Association for Music Therapy http://www.musictherapy.ca/en/
European Association of Music Therapy Students http://www.eamts.org/
World Federation of Music Therapy http://www.musictherapyworld.net/WFMT/Home.html