Centering your webpage when you've got a full size background

I just finished fixing our website so that when your browser isn't fullscreen, it will still look nice, and not all smooshed to the left side of the screen. My eyes are so crossed right now...

Here's a link to the page that I found the most helpful in my quest to center my poor webpage:
http://simplebits.com/notebook/2004/09/08/centering/

It looks perfect on our resolution of 1024x768, but I don't dare check it out on any other resolution... that might mean more coding! *gasp!* I got out of the web design business 10+ years ago, so I am completely out of date with my HTML skills. (I'm glad I chose soap as a business instead. It's stayed relatively the same for how many thousands of years? *lol*)

Note to self: when you're done uploading your changes, hit F5 before you freak out because they don't seem to have taken effect. No, just hitting 'refresh' won't always do it... I didn't think the last bit of coding I tried worked so I was ready to start all over again with another piece of coding, but then I heard my I.T. brother's voice in my head: "Diiiiid you hiiiiit F-fiiiiiiive?" (You know when Luke is stranded on Hoth and he sees Obi-Wan and Obi-Wan says "Uuuuuuuse the foooorce, Luke..."? Like that.) I've learned the whole "have you tried turning it off and then on again?" thing, now I just need to get that drilled into my brain. ;-)