This site has been very useful for me to learn more about AppleScript. Time to give back. 
This one is for those that have many international cards and/or want to see how I use a script in combination with Address Book.
It addresses two issues in Apple’s Address Book:
- country names: you no longer have many variations for country names (so: all “United States”, instead of many variations like “USA”, “US”, “United States of America”)
- country address formats: tells Address Book to use the formatting that belongs to that country (e.g. my default format is for the Netherlands, which normally means for US addresses that state is missing and zip and city are switched).
It can be run standalone or (much nicer) as a plug-in in Address Book. You can specify in the script what countries to check and what your preferred country names are. It has Growl support for the summary. The script was written on a 10.6.2 system.
http://winfred.vankuijk.net/2010/01/fixing-countries-in-address-book/
Looking forward to feedback and suggestions, I am sure there is room for improvement.