Reuters say that kids looked at porn on the Internet, using the prototype laptops provided by OLPC.
I have been told in response to that article that content filtering software on the laptops themselves will be strongly discouraged. If it is indeed implemented somewhere, it will likely be done at the gateways.
Content filtering at the point of the internet connection will be possible. It will not be standard, it will not be integrated, and it will be organised and implemented by the individual countries or organisations that are running the laptop programs.
Disclaimer: I'm just a volunteer repeating what I've heard, I don't represent OLPC.