Kindle app does not work?

I am keen on getting the Kindle app.

When I click on the "View in iTunes" button on this page

http://itunes.apple.com/us/app/kindle/id302584613?mt=8#

I see an error message "The item you requested is not currently available in the Singapore store. Would you like to change to the US store".

So I say OK, and change the store. But then it tells me that my user ID is only limited to being used in Singapore.

What gives? How do I get this app?

I spoke to the Kindle team and they said only Apple can answer this question for me. Kindle/Amazon just make the app.

Thanks for any advice.