How can I change the country of an iTunes account? When I first set up my iTunes account, I didn't have a credit card, so I set it up as a US account, as this was the only way I could create one without a card (and thus use my iPod Touch). 

The downside of this is that now that I am trying to add a credit card to my iTunes account, I can't, because it insists on a state and zip code for part of the address, which my Irish credit card obviously doesn't have.

So how can I switch the country of my iTunes account?
To change stores you can do so on the iTunes Store:


Click on your Account in the iTunes Store to go to your Account Page.
Click "Change Country or Region".
 
Choose your Country or Region:
 


Another alternative is to use Apple's Manage your Apple ID site and change your address - next time you use iTunes it will ask you to change your region and verify your address details.