I am currently working on a membership registration web form,
wherein we have to take details of the member being registered online.

i need to know his Country, State/Region and City.

i am looking for a database/list so that we can provide the same in a combobox in the registration form.

the states should on the selection of country ;and
the city should change on the selection of state.


i tried lot, but only getting list of countries or cities BUT independent not related.


Please guide.

A number of places you can get the sample code for geo location matching, i.e, ip2location and maxmind. Personally i like ip2location, http://www.ip2location.com on the supports and variety of packages.