General :: Copy One File To All Folders?

I am developing a Web-based application and have some folders that will generally reside outside of the Web accessible area of the server. However, since some people will not be able to store those folders outside of the "public_html" folder, I am looking to put a blank "index.php" inside of every folder within that section of the application. To make things easier, I would like to know if there might be a way to recursively copy one file into every folder in a certain location.

In other words, is there a command that might do something like:
Code:
> cp -R index.php /home/user/public_html/source-files/*
Basically, I want every directory inside of "source-files" to get a copy of "index.php". The directory hierarchy within "source-files" can go at least three or four levels deep, so the command would need to be recursive. I am looking for a command-line statement that I can type to perform this action.