Is it possible to have ads from Google and other ads on the same page / site? Or is this forbidden by Google?
cheers!

I believe the terms of service says it cannot have any competing ads, so if you have contextual ads being served by google, you cannot have another serivce serving up contextual ads as well. If you have banners in rotation and google serving up banner ads, those would not breach the TOS as it is not a competing service to Google.

I suggest looking over the TOS though to be sure.

Google does not allow ads that mimic the look and feel of AdSense ads to be used as alternate ads in lieu of PSAs.