If you would like to add banners to your website easily, quickly, and with all the features of a professional ad serving engine you should take a look at OpenX. You can go to OpenX here to learn more. If you have used banner serving technologies before you will realize they have all the grounds covered with features. Also in the past they were named phpAds, of course that was years ago and I loved them then. Now they also have a free version which is hosted so you no longer have to install any software. You can start today, serve ads, and have ads filled by their OpenX market place. This is a great way to add a banner internet marketing solution to your site or sites.
They also have an enterprise version and a funny video explaining what advertisers want, what publishers want and what their serving technology does. Watch it here: