Then you'll simply want to make sure your HTML layout is flexible and doesn't use strict layout settings (i.e. fixed widths and heights). Also the content displayed needs to not have hard coded line breaks accept where appropriate.
Probably the best thing to do is to just play with some big blocks of content in various page layouts and get an idea of how it behaves when you change the dimensions of the browser window (also consider the flexibility of the browser default font size).
This matter is really an HTML/styles issue. If you have more questions, you can post them in the other forums on here that apply to those areas.