Don't forget to make sure the designs look acceptable in lynx/links2 browsers

As for the screen resolution one, is't it possible to just hardcode the side bar widths only, and let the width of the main content freeflow? Is there a minimum width you can set on the freeflow area to stop weird things happenning in too narrow a window? Plus, not everyone uses browsers full-screened (or even the same size window borders/scrollbar size/toolbars etc. etc.), so you can't assume a certain window size for someone running at 1024x768