You built a great website layout which is 960px wide, and you want to centre (center for EN-US) the website using CSS instead of the dreaded <center> tag. CSS makes this really simple.
Starting with the HTML we have a div which is called wrapper which contains all the content.
The CSS is used to centre the content.
//first get rid of the padding and margin for the body
width:960px; //sets the width of the div, is required
margin: 0 auto; //sets the top and bottom to 0 and left and right to even hence the centre