Android provides accessibility features and services for helping users navigate their devices more easily, including text-to-speech, haptic feedback, gesture navigation, trackball and directional-pad navigation. Android application developers can take advantage of these services to make their applications more accessible.
Links
[1] http://adagreat.powweb.com/Registration/
[2] http://adagreat.powweb.com/Webinar/AccessibleTechnology/Schedule/