Dropdown madness

Hi all I have a project that requires me to be able to do the following.

Display a dropdown of US states, when state is selected the corresponding countys will appear in another dropdown.

Like this page: http://www.personalinjurylawyer.com/

If anyone can help me with the following I would be most appreciative.

1) Where can I buy the code that would make that happen?
or
2) Where can I buy the database so I can create the code on my own?

Thanks in advance.


cross posted.