Speaking browsers can have trouble making sense of text laid out in a table. However, since style sheets offer more powerful presentation mechanisms, the World Wide Web Consortium will eventually phase out many of HTML's presentation elements and attributes. If your audience is not well defined in terms of browser, the pragmatic approach is to use tables for layout but to be aware that these should eventually be phased out in favour of Style Sheets. Although it is superficially attractive to have navigation in one frame and page content in another, there are drawbacks to using frames. There can be problems printing a framed page.
Frames can cause problems to search engines.
There are problems with bookmarking frames as the URL of a framed site only represents the initial frameset and may not reflect the user's current view of the information. Older browsers cannot handle them and so it may be necessary to provide a 'noframes' version. Think at least twice before deciding to use frames and, if you do, make sure that you implement them properly - a badly implemented framed site can be a disaster. See also the Web Design Group's Using frames and accessible web sites. If you are using a version 4 or above browser, you will see that this page uses a style sheet which specifies a left margin except for H1 and H2.