It's not the screen resolutions you have to worry about, it's the size of
the browser window. Some users have high resolution screens, but use the
browser in smaller windows. And don't forget the side-bars which cut back
on available width.
If you use a fixed table sized to 760px width (less the width of any shared
borders you may be using) and place all your content into it most users will
be accommodated.
Use a table sized to 100% width, and the content will re-size to fit the
browser, the smallest width being determined by the width of any graphics
used.
The table may be centred to provide a left and right margin at larger window
sizes.
If you want the page to be printable on A4 paper in portrait layout, then
use 570px width (including shared borders, if any). Or use 100% and make
sure the page will squish down to 570px width without a horizontal
scroll-bar appearing.
You can setup FrontPage (from FP2000 and later) to approximately (very
approximate, but close enough) emulate a browser width by adjusting the
width of the Normal pane in FP2000/2002, or using the preset Page Size
settings on the FP task bar in FP2003.
Ron