According to the Official AER Guidelines, there are three aspects of a presentation that must be considered:
The actual verbal presentation
The handouts
Any materials that will be placed on a web site
Making Your Presentation Accessible
Keep the design simple.
Consider incorporating slide transitions that include sound. This allows audience members who are blind or visually impaired to know when you are moving to a new slide.
Verbally describe all graphics including tables, charts, and images during presentation.
Making Your Handouts Accessible
All handouts must be provided in large print and braille. Just reading the slides is not adequate.
Making Your Presentation Accessible For the Web
Create a written description (Alternative text) for all graphics including tables, charts, and images.
To post your PowerPoint to the web in an accessible format see http://cita.disability.uiuc.edu/software/office