NAICS - North American Industry Classification System.
Census Bureau website has bridge tables from this new industry coding system (NAICS) to former code (SIC).
The print editions of the manual ( 1997 ; 2002 ; 2007 ) are at the Information Services Desk (call number PREX 2.6...)
Website from OSHA (Dept. of Labor) which has keyword searching for SIC codes (1987 ed.).
The manual was last issued in 1987. Strengths were coding of manufacturing industries. Coding system replaced by NAICS. (at: PREX2.6/2:IN27/987 , 3d floor)