Follow best practice guidelines for designing Macromedia Flash content.

(see guidelines for overcoming access barriers)

Screen readers typically announce the beginning and end of each Macromedia Flash movie. Then by default, Flash Player reads text elements, buttons, and input text in Flash content.

Following is a summary of how to make your Flash content accessible. For more information see http://www.macromedia.com/resources/accessibility/

Assign text equivalents for visual elements using the Accessibility panel.
Control reading order of Macromedia Flash content so that all elements are read as a group. For example, content group, navigation and instructions. Otherwise screen readers can intermingle content, making a site very difficult to understand. Do this using ActionScript.
Use captions for audio content.
Child objects of movie clips or entire movies should be made inaccessible so that screen readers do not interpret looping elements and keep refreshing.
Try not to present information in your movie if it remains on the screen for only a short time.
Ensure keyboard access to all controls.
As sites become more complex, try to add a description for the entire movie to help orient screen reader users to the structure of the site.
As the state of a button changes, the accessibility information for the button should be updated as well.