Center align site layout using CSS

Recently I began creating 100% CSS layouts, and faced a lot of problems in getting the content to be centered in both IE and FF. After lot of googling, the final working css is :

body {
text-align:center;
} 

div#content{
text-align:left;
width:748px; 
margin:0 auto;
} 

Change "content" for the name of the enclosing div around the page content.