Country, state, location ...
 

how do i can add locations fields in this manner:

1. countries are listed normally to the user but the id stored in DB must be the country code (ex. EN, IT, DE) (consider i already have a table like [country_code,country_name] )

2. when a user choose his country, he could enter his state/province

3. now could be cool if the location is suggested (ajax) from a list of locations already typed by other users

no mod to do it?