I found a shortcut to centering something prior to the weekend. I had a 900px wide div I wanted in the center.
.centerDiv
{
width:900px;
position:absolute;
left:50%;
margin-left:-450px;
}
Put the thing dead-on center, too. Thought it was awesome.
Until I unmaximized my browser window, that is. The left side was cutoff the page, couldn't scroll to it or anything. Oh well, live and learn.
So yeah... "text-align:center;" on the outer div, "margin: 0 auto;" and "text-align:left;" on the inner div.