You should understand that Amazon, most likely, really would like to sell to anyone in the whole world. What stops them is usually the various rights issues in the various countries as well as international commerce issues and costs. But they're definitely working on it.
When they first released the Kindle just over 4 years ago, you basically couldn't effectively use it anywhere except the US and you couldn't even begin to buy a book if you were in another country without playing all sorts of questionable games with registration and ISP's. And forget about using the wireless aspect if you were a US person traveling elsewhere.
Now, the wireless is available almost anywhere there's a decent cell network, there are dedicated Kindle stores for several countries, and even in other countries you can at least buy the thing through Amazon US and have access to some books. There are even books available in languages other than English -- overall the number of titles available has gone from under 100,000 to over 1,000,000.
But there are still restrictions based on what each country and its laws allow.

It's disappointing, I understand -- but they're working on it.
