If you want accurate information such as impressions per month and how many clicks each ad recieves, I would try phpadnews. If you want just a quick code then this will do the trick.
Code:
<script type="text/javascript">
/*
Rotating Ads per Page Load
by iFusion -
(OFFLINE) Board Offline
*/
//Define the ads' URL and Image below
var ad = []
ad[0]=["URL HERE" , "IMAGE URL HERE"]
ad[1]=["URL HERE" , "IMAGE URL HERE"]
ad[2]=["URL HERE" , "IMAGE URL HERE"]
//Do not edit anything below this line
x = Math.floor(Math.random()*ad.length)
document.write("<center>")
document.write("<a href='" + ad[x][0] + "'>")
document.write("<img src='" + ad[x][1] + "' />")
document.write("</a>")
document.write("</center>")
</script>
Hope that helped!
