Security Now just concluded an amazing podcast series on the subject of cryptography.  Steve Gibson does an excellent job of making the world of crypto accessible.  No serious math is needed to understand it.  He covers everything from stream ciphers, to block ciphers, to public key cryptography and certificates.  If you have any interest in the subject, check out this six-part series:

Intro to Crypto

One Time Pads

Block Ciphers

Public Key Crypto

Cryptographic Hashes

Primes and Certificates

If you want to learn more, there are two books I recommend:

Crypto by Steven Levy - A modern history of crypto.  Levy is a great author.

Applied Cryptography by Bruce Schneier - If you want to learn how this stuff really works.  You'll need some math for this book.