How to align <div> tags?


Hi guys.

I am adding some banners to the various "Ad_" templates.

The ad network has provided some code to place in the spots were I'd like the banners to appear.

The code looks like this.
<div id="gzk504"></div>
My question is how do I tweak the position of the ads being displayed? I need to move the main leaderboard banner in the header over an inch or two. I need to center a few other banners.

Thanks for the help.