"Whenever you are creating content for mass consumption (be it students, co-workers, or the Web), you should consider the accessibility of what you are creating. For example, if your content has audio, have you created a transcript or captions so that deaf people can access it? If your content has important visual information, have you formatted this information in a way that is compatible with the assistive technology used by people who are blind or have low vision?"
Check out the Classroom Technology Inventory to see what equipment is in your classroom. For more information on audiovisual equipment check out the Audio Visual Department page: DC Audio Visual Department.