Tutorial: How to change the location (the country) of your App Store (iTunes)

For legal reasons beyond my power of imagination certain Apps are only available through the US App Store (for example 2kgames' Civilization Revolution, AppStore-Link). Here is how you can get them in a legal way:

1. Purchase an iTunes Card or Gift Certificate issued in the US. My source is igx4u.com, they send you the code through Email (not really cheap, but everything worked like a charm and they seem trustworthy; please leave a comment if you know better sources).
   
2. Set up a new account in iTunes in the store of your choice (for example US).
   
3. You then provide the code you purchased in 1. as billing option (no credit card needed) and provide an adress in the country of your choice. Best case scenario is you know someone you gives you their address, worst case scenario is google for addresses, but that might not be so legal after all).
   
4. That is it - once you sync your iPod/iPhone you will be able to install the Apps. Switch back to your original iTunes subscription, sync again and your phone will access your old iTunes store again.