Manual for Countries Code API module

Hi,

Greetings,

I wish to let users to select their country when they sign up, then I will use"view" module to produce the search result.

Is Countries Code API module (countries_api-6.x-1.1) what I need?

In addition, is the any manual teaching us how to use this module?

I have searched for http://drupal.org/project/countries_api ,but it doesn't teach us how to use it. In addition, I read through http://www.kirkdesigns.co.uk/docs/drupal-country-codes-api-module ,but doesn't get the user manual.

I have no idea about what to fill out in "value" column.
Can anyone provide me some idea?

Thanks a lot.