[support] Allowing users to select from huge lists of towns/cities in Profile

I would like to allow my users, on signing up, to be able to select their town and state from a large db of date I have. For example, a user select United States and is then given another drop down with States, chooses Florida and then can select towns in a third drop down list. Alternatively, is there another user-friendly way of allowing users to choose from 100 countries and all the towns and states within them, without resorting to free text fields, which I want to avoid. Thanks Neil