The Federal regulations related to Model Rocketry can be found at the following locations.
BATF
Bureau of Alcohol, Tobacco and Firearms Codes ???
NFTA
National Fire Protection Association (NFPA) Codes 1122 (for model rocket motors) and 1127 (for high-power rocket motors)
Internet: http://www.wpi.edu/~fpe/nfpa.html
FAA
Federal Aviation Regulations Part 101 (Section 307, 72 Statute 749, 49 United States Code 1348, "Airspace Control and Facilities," Federal Aviation Act of 1958)