http://www.neogaf.com/forum/showthread.php?p=8920000#post8920000
I included (what I hope is) a handy guide for people who live outside Japan and want to pick up GT5: Prologue.
-FYI: Some people's credit cards DO work on foreign stores with an incorrect address.
To get GT5: Prologue off the Japan Store:
Note that I have not done this but I have tried to go through as much of the buying process as possible without having my own PSN Card. You're on your own after step 6.
This is not an all-inclusive guide and I am not responsible for any mistakes you make in the buying process.
1)
Set up a Japan Store account.
Alternate guide here.
2) Try your credit card on the Japanese Store or buy a Japanese PSN card
HERE or
HERE or
HERE or
HERE or
HERE or
HERE or
HERE or
HERE or
HERE. (see additional notes about this step below)
3) Select GT5: Prologue and Add it to your cart.
4) Go to check out and start by clicking the option on the right.
5) Continue clicking until you get to a page with 3 options.
6) Pick the third option and enter your PSN Card code.
7) Finish the checkout process and download the game when you see the list with GT5: Prologue in it.
NCSX importers email you the code and don't charge shipping. When ordering, the freight charges that show initially will only disappear shortly before you get to the final checkout page. NCSX also currently appears to be out of stock of 3000 yen cards.
Playasia DOES charge for shipping and you have to wait a few days to get your card. However, they have more options for the denominations.