An old girlfriend of mine was an instructor of NLP, and I really didn't buy into it very much. It is all a bit too new agey hippy for me. That said, the broad principal of it seems sensible enough in that you by a careful choice of words you can influence the emphasis of certain points. Also by knowing the person that you are communicating with you can word your points in a way that appeals to their character.
The choice of words bit is interesting, and is useful. For example it is suggested that if you give someone an instruction or a reminder about something you should say "remember to do such and such" rather than "don't forget to do...." (unless of course you want them to forget to do whatever).
The second bit is that people learn and listen in one of (or a combination of) 3 ways: auditory, visual or kinesthetic (emotionally), so if you can work out which one of those is most pertinent to the person you are talking to you can tailor your phraseology to them, particularly if you are trying to win their support on a particular point, or trying to get them to do something that they may be a bit reluctant to agree to. For instance if the person you are talking to is visual you would make visual references such as "so you can see that when we do this we will be here in relation to..." or "people will see this outcome" where as if they are kinesthetic you would say something like "if we do this it will make me feel safe" and if they are auditory you might say "when we have done this you will hear....".
That as I understand it is NLP in a nut shell. It is widely used by salesmen and women to help them achieve a sale (perhaps that is the Dark Side of a Jedi type skill), but I feel it is not so much a science as a way of trying to turn something that most of us do somewhat instinctively into a commercial science (courses and books abound on the subject), although a little understanding of some of our instincts can maybe help us communicate more effectively. I wonder...