NLP is a method of influencing brain behaviour (the "neuro" part of the phrase) through the use of language (the "linguistic" part) and other types of communication to enable a person to "recode" the way the brain responds to stimuli (that's the "programming") and manifest new and better behaviours.
Neuro-Linguistic Programming often incorporates hypnosis and self-hypnosis to help achieve the change (or "programming") that is wanted.
Dr Richard Bandler invented the term "Neuro-Linguistic Programming" in the 1970s. He was recently asked to write the definition of Neuro-Linguistic Programming that appears in the Oxford English Dictionary. It says:
Neuro-Linguistic Programming: "a model of interpersonal communication chiefly concerned with the relationship between successful patterns of behaviour and the subjective experiences (esp. patterns of thought) underlying them" and "a system of alternative therapy based on this which seeks to educate people in self-awareness and effective communication, and to change their patterns of mental and emotional behaviour."
Neuro-Linguistic Programming is used to enhance performance, to help an individual control their emotional state and to stay focussed on what they want from life. It incorporates specific Neuro-Linguistic Programming strategies and techniques designed to produce specific outcomes. For example, the famous Neuro-Linguistic Programming "Fast Phobia Cure" has a very different set of techniques in comparison with the Neuro-Linguistic Programming "Motivation Strategy."
In short, Neuro-Linguistic Programming allows people to have more choices about their lives. For that reason, Dr Bandler, the inventor of the term "Neuro-Linguistic Programming", likes to say that "most of all, Neuro-Linguistic Programming is about freedom".