No matter how you code the HTML for the web page, WYSI No tWYG, i.e.. "What you see in Internet Explorer ver 5.x or Netscape 4.x browsers will not be what you get on the TV screen"!!
We need a series of "work arounds" to start the process.
Remember the final result is what you see on your TV set using the "WEBTV" or "Microsoft TV"set top box.

The coding standards for the Sony WebTV and Microsoft TV set top boxes are as follows:

See a short description of each of the above standards, derived from the Microsoft CD "Interactive Television Workshop, 12.14.99.

Screen Size
The active area on the TV screen is 560 x 420 pixels .
The useful area in TV Mode is 560 x 420 pixels.
The useful area in Web Mode is about 544x 372 pixels.

A very good explanation about of TV screen sizes and resolution can be found in the WEBTV developer site. http://developer.webtv.net/design/resolution/resolution.htm.
View a local copy of this page.

Screen Size Considerations In Web Mode

How To Start The Process
a. Firstly, open a graphics editing program, such as Photoshop, and layout an area of 560 x420 pixels.
Then create a 3mm wide rectangle of 544 x 372 pixels to show a "safe area" that outlines the worst case viewable screen area to accommodate various TV sets. This represents a 90% safe area.
b. Draw rectangles to represent the TV Picture-In-Picture screen area, graphics text areas and layers. This give an idea of relative sizes of the elements.
c. Write down the x,y coordinates ( this represents top and left attributes for placement)
d. Place the image ( gif or jpg) in a generic HTML page and view the HTML file in the MICROSOFT TV Simulator. (File size=9MB).
e. Then view the page in the actual TV set using the set top box. View the test image in the Microsoft TV in the Simulator first, then in the actual TV set using the set top box.

Conversions to TV and WebTV Screen Resolutions
Televisions have a smaller screen resolution than computer monitors, and the WebTV browser does not allow horizontal scrollbars.
This means that all Web page content must be compressed or otherwise made to fit in a 544 pixel-wide space. The WebTV browser applies different rules to do this as gracefully as possible, but problems can sometimes arise.
HTML text is never compressed with the WebTV or Microsoft TV browser. Text will be "re-flowed" to fit the space it is allotted, but the size of the HTML text will change depending on how it is coded. See the next section on Coding Text.
Conversely, single images may be compressed to make them fit into a 544 pixel-wide space.

Web pages can be scrolled using the WebTV controller when the Web page is viewed in "Web Mode". There is no scrolling function if the Web page is in "TV mode".
See the section on Sample Pages for more details.

REFERENCES
1. The WEBTV site has a good overview of coding for the Sony WEBTV set top box. Go to http://developer.webtv.net/
2. The new MicrosoftTV Platform site: http://www.microsoft.com/tv/ contains new information on Microsoft''s Interactive TV.
For reference purposes visit the Microsoft TV Advanced Content Developer Kit (CDK) Beta site http://premium.microsoft.com/tv/contentdev/cdk/default.asp. It is shown here only for reference.This web page contains broken links!!
3. Web TV ITV web site has many examples of templates for Microsoft TV . Go to http://itv.webtv.net/
4. An excellent source book is Building Interactive Entertainment and E-Commerce content for Microsoft TV, by Peter     Krebs, Charlie Kindschi, Julie Hammerquist. Published by Microsoft Press, 2000. ISBN 0-7356-0628-5
5. Search Altavist, Google or Techcrawler for "webtv authoring".
6. Some specific topics:
    General Authoring: http://developer.webtv.net/authoring/