I have a simple php rotate script if you want it : Works best with banners of the same size :

Step one: create a folder (in this case i used rotate1) so http://yoursite.com/rotate1/

Step two: create file called rotate.php and enter this text ::

Code:
<?php/*
By Matt Mullenweg > http://photomatt.net
Inspired by Dan Benjamin > http://hiveware.com/imagerotator.php
Latest version always at:


http://photomatt.net/scripts/randomimage


*/// Make this the relative path to the images, like "../img" or "random/images/".
// If the images are in the same directory, leave it blank.
$folder = '';


// Space seperated list of extensions, you probably won't have to change this.
$exts = 'html';


$files = array(); $i = -1; // Initialize some variables
if ('' == $folder) $folder = './';


$handle = opendir($folder);
$exts = explode(' ', $exts);
while (false !== ($file = readdir($handle))) {
foreach($exts as $ext) { // for each extension check the extension
if (preg_match('/\.'.$ext.'$/i', $file, $test)) { // faster than ereg, case insensitive
$files[] = $file; // it's good
++$i;
}
}
}
closedir($handle); // We're not using it anymore
mt_srand((double)microtime()*1000000); // seed for PHP < 4.2
$rand = mt_rand(0, $i); // $i was incremented as we went along


header('Location: '.$folder.$files[$rand]); // Voila!
?>
Step 3: Make html files each file with the banner code you want and name them 1.html .html exc
They must be in the same folder as the php script you created... and works best with numbers only!!

Step 4: Add the iframe code to where you want the banner ::

Code:
<center><iframe src="http://Yoursite.com/rotate1/rotate.php" width="500" height="100" frameBorder="0"><p>Place a non iframe banner (without flash or java here so a banner will always show if the users browser does not support these</p>
</iframe>
Make sure you change the iframe size! You need it slightly bigger than the banner.