IMPORTANT: This project is still in Beta, I still have a couple of issues to iron out before it is ready to use in a production environment! However you are more than welcome to use it for purposes of testing. Download from SourceForge.
Download and extract the file(s) in a directory called RotatingBanner in your extensions/ folder.
Add the following code at the bottom of your LocalSettings.php:
require_once( "$IP/extensions/RotatingBanner/RotatingBanner.php" );
Open the "Vector.php" file and find the following (around line 163);
<div id="mw-page-base" class="noprint">
<div id="mw-page-base" class="noprint">
Directly below this paste;
<?php include './extensions/RotatingBanner/includes/RotatingBanner.php';?>
Find the following (around line 73);
$out->addModuleStyles( $styles );
And directly below paste;
$out->addModuleStyles( 'ext.RotatingBanner' );
Return to MediaWiki refresh the browser (Shift + Ctrl + R for Chrome and Firefox).
If there's a problem navigate to "Special:Version" on your Wiki to verify that the extension is successfully installed. Problems are normally due to mistakes editing Vector!
Replace the advert/images for your own, found in extensions/RotatingBanner/images. Edit the banner links by modifying extensions/RotatingBanner/includes/RotatingBanner.php, you may also need to tweak the css a little, /extensions/RotatingBanner/modules/ext.RotatingBanner.css
Support, queries and questions requests via the contact page (above).
Mail me to be added to the mailing list so I can let you know when the extension is stable.