How to use CSS to vertically allign...?

I have a site that I would like to valign but am not sure how to go about it… I read the tutorial on the kirupa site but that did not work… so what i have so far is…

div#main {
margin-top: auto;
margin-bottom: auto;
height: 100%;

but all that displays is my content at the top of the page… please help!

also if there is another way other then CSS i will take your help :slight_smile:

thank you