North American Fuzzy Information Processing Society (NAFIPS)
From the website:
As the premier fuzzy society in North America established in 1981, our purpose is to help guide and encourage the development of fuzzy sets and related technologies for the benefit of mankind. In this role, we understand the importance of, and the need for, developing a strong intellectual basis and encouraging new and innovative applications. In addition, we acknowledge our leadership role to foster interaction and technology transfer to other national and international organizations to bring the benefits of this technology to North America and the world.
Links, pointers to software, journals, etc.