Using Web Templatess for Web Design: Tips and Best Practices-- Frames
Do not include frames in Web sites, unless there is a strong (clearly defensible) reason to do so.
Use frames only when other design solutions are not adequate. Frames may take longer to design, develop, and maintain. Splitting a page into frames can be confusing for users since frames can break the fundamental user model. Frames can yield unexpected results, particularly when using the "Back" button. Frames make a Web site difficult to use, and can prevent users from emailing a URL to others.