Originally Posted by Geezer D
The large open space at the bottom is generated from your #outerbox margin. To remove it, you need to specify the bottom margin separately from the top. Margin: 120px auto applies a 120 pixel margin to both the top and bottom. Adding a third number to the margin attribute will apply a separate margin value to the bottom margin.
background: url(images/main_header.jpg) no-repeat center top;
margin:120px auto 0px;
Looking at your code, Firefox is displaying it properly while IE is doing it's own thing.
Hope this helps!