Each state has a state Assistive Technology Act (AT Act) Center. These centers have been funded by the National Institute on Disability and Rehabilitation Research (NIDRR) as part of the Assistive Technology Act of 1998. To locate an AT Act Center in your state, consult the State Tech ACT Projects.
The Association of Assistive Technology Act Programs (ATAP) includes most of the projects, but membership is voluntary. The mission of ATAP is "to set the national direction and advocate for AT Act programs. ATAP will promote and support quality performance of the State AT programs."
Another resource is The Alliance for Technology Access(ATA). ATA is a network of community-based resource centers, product developers and distributors, and associations devoted to providing information and support services to people with disabilities and increasing the awareness and use of assistive technology.