BuddyPress.org

Hello. I’m using BP 1.2.5.2 and WP 3.0. I want to add some features to the registration page. What I want to do is that:

For example, user is selecting country section. When it selects e.g. USA, I want the State field to change to USA’s states which I created before. I mean if user selects Germany, I want State field to list Germany’s cities e.g. I want such a function for my registration page. How to do that? Thank you. Best.