This is a pretty simple layout. But copying code from a website won't help unless you understand the code.
Around all of the separate divs you have (header, you are here, menu, content, and footer), you will want to have a 'wrapper' div. Why wrapper? Because it wraps around everything. Give the wrapper div a width, which will be the width throughout. Make the wrapper's margins on the left and on the right auto to get it centered.
Because the header and everything else are going to be separate, I would put another div around everything else, so you can give it a separate background from the header div.
In the everything else div, you will have four divs (you can probably use less, but this is just what i do).
For the you are here bar, just give it a height and I think you will be ok.
For the menu, give it a width and float it left. Give content the menu's width subtracted from the wrapper's width. Float left (This way if you want to add another column, you just add it and float it, and it will pretty much work off that bat).
Then for the footer, you will want to give it 'clear:both' and of course a height. This will make sure that it is clear from both the menu and the content divs, because they are floated.
That's the general idea, I think. Feel free to correct anything that seems wrong. This should work for all browsers.
Edit: If you do encounter IE 6 or 7 problems, make a separate css file called 'iestyle.css' or something. Here's how you put it in the html:
<link href="style.css" rel="stylesheet" type="text/css" />
<!--[if IE 6]><link href="iestyle.css" rel="stylesheet" type="text/css" /><![endif]-->
<!--[if IE 7]><link href="ie7style.css" rel="stylesheet" type="text/css" /><![endif]-->
This way you only have to put the changes you want to make for Internet Explorer in their specific css file (all the other stuff that will be kept the same doesn't need to be in the ie style). This is because all the normal css is loaded first (style.css), and then the specifics are overridden if it is internet explorer 6 or 7. No hacks, just extra style sheets.