NVC is both un-organized and has some structure around organizations and events. CNVC is the center founded by Marshall Rosenberg, and this is the place that organizes certification of NVC trainers, International Intensive Trainings and more. There are some hundreds of trainers worldwide, who individually or some together organize trainings, workshops and other development work, some also in businesses. Apart from the trainers there are many NVC practitioners who have had training in one or more training workshops and who organize practice groups, festivals and other kinds of work or just take NVC into their daily family and work lives. On the Internet you will find a variety of websites, and most probably there will be one or more options available for you locally.
Here are some Internet websites:
The Center for Nonviolent Communication: http://www.cnvc.org
Puddle Dancer Press (Marshall Rosenberg): http://www.nonviolentcommunication.com
NVC Academy: http://www.nvctraining.com