Outsourcing Banner Ads?

phoneboy asks: "I'm looking for solutions that will allow me to outsource most of the work in having banner ads (maintaining the banners and the billing) while allowing me to keep some of the money actually made from the banners. I don't even necessarily need people to "sell" banners for me, though that might be a nice service to have as well. Are there any decent banner ad services that will work in this manner? What are your experiences with these services? Can someone give me an idea of what any of this might cost? Your thoughts are appreciated." If you're currently running a Web site that's becoming a drain on the wallet, you might want to pay attention to this one.