Schneier wrote Applied Cryptography, which is the best way to get started in the field. I picked it up while I was still learning programming (and not exactly confident in my math abilities) and still found it incredibly well written and understandable.

http://www.schneier.com/book-applied.html

From the Preface:

"I wrote Applied Cryptography to be a both a lively introduction to the field of cryptography and a comprehensive reference work."