I am an qualified NLP Practitioner and you are right there is a lot of nonsense attributed to NLP. There are also some strange people on the fringes, there are also people who want to make money.
NLP originates in therapy, and it is a veryversatile toolbox for dealing with a number of issues. Some of which are transferable to the classroom. There are loads of books on NLP and teaching in school and many of them are available at low/sale prices. I have even seen one or two on ELT.
The value of NLP in the classroom is helping students develop learning habits and learning skills. Especially good for when students convince themselves that they cannot do it. Other parts of NLP are 'applied common sense'. For example the use of different representational systems to assist learning (practical application of Gardner's multiple inteligences). i.e. using all five senses in learning, including kinestetic (running around, playing games, handling realia etc)
You can spend lots on books, some are good, other are almost a cut and paste of what has gone before. But a really good online resource is in the link below.
http://www.nlpuniversitypress.com/
You can only open so many pages and it tells you can see no more. Just close your browser and visit the site again for your next installment.
Some of the people involved in NLP genuinely want to help other reach thier potential, other like me investigated it and have drifted away