Code to retrieve selected country for shipping address from Magento user details

How would I retrieve this information from a users d开发者_StackOverflow中文版etails when they save their account? I found a tutorial online and followed that to build an observer for the customer before save event (I'm not sure this is the correct event to observe, but maybe!).

http://www.fontis.com.au/blog/magento/automatically-set-magento-customer-group

But how do I get the value the user has selected as the country of their shipping address?

The idea here is to assign a customer into a customer group based on their shipping address (country).

Any help appreciated!

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It seems this question is redundant in my scenario as Magento's tax classes achieve what I was trying to work out here. Tax based on shipping address :-)