There are many excellent traditional and online resources available. This is a small introduction.
The CodeBreakers by David Kahn
Applied Cryptography (2nd Edition) by Bruce Schneier
alt.politics.datahighway
alt.privacy
alt.security
alt.society.civil-liberty
comp.org.eff
comp.society.privacy
comp. security
sci.crypt
Government/NonProfit
The National Security Agency Web Page (NSA)
The Cypherpunks
Center for Democracy and Technology (CDT)
Electronic Privacy Information Center (EPIC)
Electronic Frontier Foundation
Computer Professionals for Social Responsibility
Privacy International
Private Industry
RSA Data Security
Counterpane Systems
Cybercash
Cygnus Support
Digicash
Science Applications International Corp (SAIC)
Motorola Information Security Operations
Other
Ronald Rivest's Crypto & Security List
Encryption Policy Resource Page
Quadralay's Cryptography Archive
Home
Cryptography Defined/A Brief History of Cryptography
Popular Algorithms & How They Work
Key Length - How Long is Long Enough?
Cryptography in Everyday Life
America's Social/Political Debate