Many applications require a MySQL table of all the countries in the world and their corresponding country codes, but compiling that manually would be a bit of a chore!
You can view an up-to-date full list of the countries available and their associated codes on the ISO Online Browsing, but to save you some typing time see a MySQL database table export below:
Countries.sql 6.1kb - Download
Copy the contents of the above file into the 'Contents' tab in phpMyAdmin, or use the 'Import' tab to upload the file directly. See 'next' link below for importing via command line.