There is no consistent way around screen size issues because everyone has different monitors on different settings.
The best way around it is to decide on a minimum resolution that you will support, lets say 800x600, or 1024x768. Once you choose one, make sure every page looks ok in that resolution (so that your lowest rez user, 800x600, will not have the horizontal scroll bar), then I would normally use a table for the overall page, and set the width to 100%, or close to it. That way it will stretch to fit even the highest rez users, but will still work with the lower ones. Pages optimized for low res can look a little sparse when stretched to 1280 or so, mind you, but it does distribute on the page.
You can also just pick a width, it used to be fairly standard to design in approx 800 pixels wide, and set your main table for that. It would fill the screen on the lower end, and higher rez would just show empty background one each side (if you center).
If this is sounds confusing, think of it this way. Imagine a piece of dowel about 30" long and holding it out in front of you horizontally with both hands. Now imagine, while holding it out with both hands, walking through about 1000 doorways. There are some standards, and most of the time that dowel would fit fairly well, but there would be times when it would be too small, and others when it would too large.