Can I Add Revolving Ad Banner?

[Steve038]

I have a few different advertisers who I'd like to display their advertising banners just below the Navbar. You'll see one currently on my site here for Monster Race Wear: http://www.theroaringseason.com/forum.php

What do I need to do to allow other advertisers banners to appear in this same spot randomly? Sorry, I don't know what the correct terminology is, but basically I want my different advertisers banners to appear randomly in this same spot when different pages are viewed, by different people. I don't want them to change from one banner to another while the page is open, I just want to create it so an advertisers banner appears randomly in the spot when a page is visited, then when the same visitor opens the same page at another time, or refreshes the page, a different advertisers banner appears?

I've been playing with the options within the Control Panel under Advertising>Manage Ads, and this lets me add multiple ads, but they all seem to get displayed at the same time, one beneath the other, cascading down the page, which obviously isn't what I want.

Here is a good example of what I'm trying to achieve on this site: http://www.pro-touring.com/forum.php When you refresh the page, a different banner ad appears. I want to achieve this.

Any help here would be appreciated.