Starting up a project

When starting a new project what reolution should I make the stage so when displayed in inetrnet explorer and netscape it appears without being skewed and without scroll bars at the sides. I’ve tried making it 1024 x 768 but I just keep on getting massive scrollbars to compensate for the browser window. Is this something to do with the options in publishing or is there some code I can enter so the background (imported picture) fills the browser window no matter what size it is???
Help me!!!