[Dolby]

I use phpadsnew. It has a high learning curve but after playing with it for a few hours everything made sense. Its fairly similar to many of the ad networks like burstmedia, fastclick, etc.

Phpadsnew gives you many great features. It has geotargeting so you can show certain ads to certain countrys. You can set a CPM or CPC for an ad and many other cool variables. You can give advertisers logins so they can track the stats (same for web publishers). You can also use it to advertise with multiple ad networks. They have more features listed on their webpage so go read them .