Postcode, city, state customization

[yokozuna]

I am needing some help. I want to control the user registration form so the correct suburb and post code are populated.

I am based in Australia and my customers are the same.

I want the customer to firstly select the state they live in e.g. New South Wales from a combo box, then a listing of suburbs will be populated in a combo box based on the state they previously selected. When they select the suburb, the post code(s) will automatically be populated for that suburb.

I have a dump of all the city, state, postcodes from Australia Post.

I will need to create tables in MySQL and change the user registration form and any other forms ie during shipping to support this function.

Thanks