4
Not too sure about intergration (check forums) but I use PHPAdsNew 2.0.
It's standalone, and very functional. You can see this running at my site,
CheshAIR.com. It can show ads, google ads, flash (although I've not had success with flash and links working).
The code for the ads can be put into a block and be added to the permissions. On my site, only guests see the ads, they are not visible to registered users, although I may change that if I can make the ads less intrusive, like living down the right hand side of the screen away from main text.