Web Software: Understanding and Applying --- Frames

Understanding and Applying Section 508 Standards
Using Frames:
(i) Frames shall be titled with text that facilitates frame identification and navigation.
Frames provide a means of visually dividing the computer screen into distinct areas that can be separately rewritten. Unfortunately, frames can also present difficulties for users with disabilities when those frames are not easily identifiable to assistive technology. For instance, a popular use of frames is to create "navigational bars" in a fixed position on the screen and have the content of the web site retrievable by activating one of those navigational buttons. The new content is displayed another area of the screen. Because the navigational bar doesn't change, it provides a stable "frame-of-reference" for users and makes navigation much easier. However, users with disabilities may become lost if the differences between the two frames are not clearly established.
…
While Section 508 guidelines require that frames be titled and labeled to identify the changing areas of information, the WAC recommends that web developers avoid using frames in most cases. Instead, templates can be developed to manage repeating information (such as background color, logos, and navigation menus) across the site.
Full Article