Any suggestions for a good ad serving script?

Here's what I need:

Preferably an open-source ad serving script capable of serving up banners of various sizes on a small website. While open-source would be nice, we're more than willing to pay for a good product if it's a better solution.

Ideally this could also be able to invoice the advertiser automatically.

I've looked at phpAdsNew, but it looks like there's no invoicing/charging functionality. Can anyone vouch for phpAdsNew or another product?

 

I personally like phpAdsNew and have only heard good things about it.

 

IMO phpAdsNew is not easy to understand. Check out Revsense (http://www.w3matter.com/products/adrevenue)

 

phpAdsNew is the way to go. After trying several open source solutions, this one is the best.

 

I've also heard phpadsnew is the best.

 

I use phpadsnew of my site