Manufacturers:

Beltone
Gn Resound
Unitron Hearing
Widex
Starkey
Oticon
Siemens
Phonak
Sennheiser
Assistive Listening Device Systems (ALDS)

Associations and Organizations:

American Auditory Society (AAS)
American Speech-Language-Hearing Assoc.(ASHA)
American Tinnitus Assoc. (ATA)
Canadian Association of the Deaf (CAD)
Canadian Association of Speech-Language Pathologists and Audiologists (CASLPA)
Canadian Hard of Hearing Association
The Canadian Hearing Instrument Practitioners Society (CHIPS)
Canadian Hearing Society 
Hearing Aid Society of Nova Scotia
International Hearing Society (IHS)
League for the Hard of Hearing
National Association of the Deaf (NAD)
National Captioning Institute (NCI)
National Cued Speech Association (NCSA)
National Hearing Conservation Association (NHCA)
National Institute of Deafness and Other Communication Disorders (NIDCD)
Self Help for Hard of Hearing People
Sight and Hearing Association