I think we can file this one under 'Just because I can.' Erica Sadun has written a perl script that allows you to change your currently selected country in
the iTunes Music Store. Both iTunes and Safari have to be open for this script to function.
If you aren't a Terminal jockey you can just pop open the iTunes Music Store and choose your country from the pop up menu at the bottom of the main page, but who likes using GUI's anymore?