Phonetics is a notoriously technical discipline, and most books on the subject will make the beginner's head spin. Ladefoged's "A Course in Phonetics" is not one of those books. I believe this is the best introductory book to phonetics available. It's easy to read and he doesn't overload the reader with lots of technical terms.
Professor ladefoged uses simple plain English to describe phenomena that takes other writers half a dictionary to describe. The concepts aren't watered down, so this is the perfect introduction to phonetics.