filtering proxy

I need a filtering proxy written in c++ or python if it can be compiled. You can use any open source package that has a small footprint and is not GPL as i want the option of not release my source code. I will need the package to run on Windows, Linux and OSX. In the future I will try running on Android, Symbian and Iphone. One package you can use maybe webcleaner but i am not sure if you can compile the python code without breaking it. The filtering proxy will read a website for 1) certian timing to permit internet access 2) which sites to block url 3) which users can use the filtering proxy. User will hve to login with a email address or userid and password. Pls ensure that the password is not stored in the browser's cache. For demo purposes pls ensure that the filtering proxy can be ran from a remote server on the internet.