Note that this quote - ISO 3166-1 [1] specifies "ZZ" as "User-assigned code elements are codes at the disposal of users who need to add further names of countries, territories, or other geographical entities to their in-house application of ISO 3166-1, and the ISO 3166/MA will never use these codes in the updating process of the standard.". [1] <http://en.wikipedia.org/wiki/ISO_3166-1> is a bit short on the details. The standard ISO 3166-1:2006(E/F) actually says: 8.1.3 User-assigned code elements If users need code elements to represent country names not included in this part of ISO 3166, the series of letters AA, QM to QZ, XA to XZ, and ZZ, and the series AAA to AAZ, QMA to QZZ, XAA to XZZ, and ZZA to ZZZ respectively, and the series of numbers 900 to 999 are available. These users should inform the ISO 3166/MA of such use. Short of buying the standard documents, some more details about 3166 and user-assigned code elements can be found at: <http://www.iso.org/iso/customizing_iso_3166-1.htm>. jaap