I'm beginning to think you don't know the answer when you post these silly responses. If you're going to bother responding, at least provide a link or help the OP in some way. Even though I knew the answer, as a test, I picked some search parameters (maximum apps iPhone 4.0 folders) and the results didn't just pop out with an answer. You essentially have to find that the maximum number of apps is now 2,160 and deduce from that the answer is 12, since 180 apps are allowed without folders.
Thanks everyone. I did see posts about there being 12 apps maximum per folder through the calculation of 2160 apps allowed to be browsed in total divided by home screen icons plus 4 icon dock, etc. I just was not sure if that was indeed confirmed by someone using the beta version.
I'm beginning to think you don't know the answer when you post these silly responses. If you're going to bother responding, at least provide a link or help the OP in some way.