If you are interested in coding correctly (and most importantly, easily) I sujest moving all of you CSS styles into a style sheet that would look like this;
This would all be in a CSS file you could name style.css. Then in your html file you would include the CSS with the line ...
<link href="style.css" rel="stylesheet" type="text/css">
This would be in your html <head>
Then you could link to your styles like this
As for the IE and FF, in your style sheet, include a statment that looks like this;
that will tell FF and NS to have no margins on the page and you can adjust the location of the header accordingly.
And just as we declared the margins for the <BODY> tag, you can do the same for all other tags - ex, <TR> and <TD> as well as <H1> and <H2> - so you can define in your style sheet to have no margins, no borders, so everything will look alike.
Hope that answers all you q's