Add <center> tags to your templates starting at the beginning and ending at the end of the <body>. Typically in Act_Primary, Act_BrochurePrimary, Act_PrimaryCart etc.
Out of interest, what's your motivation behind wanting to do it?
Centred sites that are a fixed width can work very well due to the amount of "white space" on both sides of the content. Too many sites try and cram way too much on the page which can be very confusing to the user - a site with lots of white space can be very powerful when designed with care and attention.
Comment