Creating Accessible Frames
http://www.webaim.org/techniques/frames/

WebAIM
2003

Abstract:

A frameset is a Web page which defines a collection of at least two other separate Web pages, which are combined in the same visual space. Visual users usually experience framesets as a cohesive entity. They can scan the contents of multiple pages all at once. Those using screen readers cannot quickly scan the contents of multiple pages. All of the content is experienced in a linear fashion, one frame at a time. Frames are not inaccessible to modern screen readers, but they can be disorienting.