Here are some professional associations who's focus is on business information systems:
Association of Information Technology Professionals (AITP)
"At AITP, we bring together the brightest minds in technology, fostering a community where innovation thrives and professionals grow. With chapters scattered across the country, AITP is dedicated to supporting IT leaders at every stage of their career, from those just starting out to seasoned experts."
Association for Information Systems
"The Association for Information Systems (AIS) serves society through the advancement of knowledge and the promotion of excellence in the practice and study of information systems. AIS is the premier professional association for individuals and organizations who lead the research, teaching, practice, and study of information systems worldwide."
International Association for Computer Information Systems
"We value activities that develop the knowledge and skills of information systems and technology academics, by providing a forum for networking and discussing research ideas and findings, encouraging the sharing of teaching best practices, and supporting the development of high quality curriculum."
ACM Special Interest Group on MIS
"The ACM Special Interest Group (SIG) on Management Information Systems (MIS) promotes best-practice and research in the management of information systems and technologies in management commerce. SIGMIS is a founder of ISWorld Net at www.isworld.org, and a sponsor of several conferences on information systems and technology. "
Association for Information Science and Technology
"The Association for Information Science and Technology (ASIS&T) is the only professional association that bridges the gap between information science practice and research. For nearly 85 years, ASIS&T has been leading the search for new and better theories, techniques, and technologies to improve access to information."