[eluser]Otemu[/eluser]
Hi,
You would probably have better answers if you post this in the code section of the forum. However I can give you the basic concept of what you will need to do. Since the member site is already setup I assume you must have some knowledge of how to insert records into the database and return results.
When a user chooses country you need to add this to there record in the database, so if you have a user table that holds various information name, password, email, etc., then you should have a empty field for country, once there go to edit there profile saving there selected country this should be added to the database.
Now when members view there profile, all you need to do is return the country in the results, most likely you should have an image folder with all the flags so you could do something simple like images/flags/france.jpg so whatever country they choose will return the appropriate flag imag.
when returning results on the member page you can test if the returned array country is blank or not, this way if blank then you don't show there flag/country however if it isn't empty then you do.
Hope that helps