Your web kit is probably putting your page in a table and sizing it according to the typical screen sizes. You may find, however, that even the old standard 1024x768 (the old television-shaped monitor) is too wide to comfortably read across the entire screen. When I put up web pages I choose the size of the table I want to use and if someone displays my table on their full screen the table constrains the size of the box with the text in it.

I typically make the tables about 800 pixels wide and don't put a height on it - people will scroll down but they are much less willing to scroll sideways. So you could go 800 and not put in a height and it would probably look good.

This page of links goes to regular web newsletters put out at my university. Click on any of them and you'll see that the message is constrained in a table. It's easy to read, like the width of a book page, not text that goes as wide as the monitor and makes your eyes and brain work a lot harder.

SRS