How to change the default programs that are associated with every new user that is created?

I am wondering how one would go about changing the default programs that are associated with every new user that is created. For example, Firefox is the default browser for Ubuntu 11.10. In my user account I changed it so that Google Chrome is the default, and it appears in the launcher when I log in. But if I were to make another account for someone else the new user would have Firefox as the default, and it would be in the launcher. How do I get Google Chrome to be in the launcher and the default browser for every new user that is made? Thanks in advance!