I always like to give an example as well rather than a link so here's one
As you already have text-align:center in the body then your page will center in ie but you need to margin-left:auto and margin-right auto on a container with specified width in order to centre in compliant browsers.
As you already had an unused class called "all" I've used that and changed it to an id as it will be unique.
This wraps up all the content you want centred and will therefore centre it all.
font: 13px/1.5em "Verdana", Arial, Helvetica, sans-serif;
border: 0px none;
text-align: center;/*center for ie5 and 5.5. and */
margin-left:auto;/*center for compliant browsers */
margin-right:auto;/*center for compliant browsers */
Hopefuly, if you followed the instructions you will have a centred page. You could have just centred each element and avoided using a whole page wrapper but the technique is the same.
<div class="logo"><a href="http://www.theaterhopper.com"><img src="images/logo_clear2.gif" alt="Home" width="262" height="92" border="0"></img></a></div>
etc..all the rest of page until here......................
Hope that helps.