Music therapy can be powerful. Here some links to get started.
American Music Therapy Association
A website with many resources.
Big Book of Music Therapy Songs
Helping children of all abilities learning and grow through music. With Youtube videos.
Music as Therapy: How Music Can Make You Healthier
A short discussion with links.
Music therapy benefits
A center for child therapy lists the benefits of using music.
Rebecca Center for Music Therapy
Links to some research articles.
World Federation of Music Therapy
Has a nice resource center.
Music therapy on video
From the British Association for Music Therapy