Music Education Advocacy Resources:
Here is a list of links that include a variety of resources and research to assist you with your music advocacy efforts:
Broader Minded
National Association for Music Education
NJ Arts Education Partnership
Quadrant Research
Artsedge Kennedy Center
NAMM Foundation
Children's Music Workshop (Advocacy Page)
VH1 Save the Music Foundation
Music for All 
Get Banded (Jupiter Instruments)
Music In Schools Today
School Music Matters (part of Music K-8)