National Resources:

Federal Communications Commission (FCC) – The federal agency charged with enforcing federal regulations that concern the telecommunications industry
http://www.fcc.gov/

National Emergency Number Association (NENA) - NENA's mission is to foster the technological advancement, availability, and implementation of a universal emergency telephone number system.
www.nena.org/

NENA ICE 5 Press Release (pdf)

APCO - http://www.apco911.org