There are areas of accessibility that are very technical but for usability practitioners the good news is you can get on with doing what you are good at, that is research without worrying about what all those WCAG checkpoints mean or how to use a screen reader.
In this presentation for the UK UPA in September 2011, I talk about how to integrate people with access needs into user research. Specifically the presentation covered including people with Dyslexia in personas.
Read the slides on slide share.
View the captioned video on YouTube.