There's kind of two questions here...

1)If I buy a UK Kindle, can I buy eBooks from Amazon.com?
2)If I buy a US Kindle, am I locked to Amazon.com?

For using Kindle APPs on PC, etc, I figure you can get an account anywhere? But how's it work with actual Kindle hardware?
Also, if you already have a Kindle account (say for PC or iPad) and then buy a handset, can you choose what account the handset connects to or does it come locked to a brand new account, meaning you can't access your books?

Oh... and does Kindle get software/firmware updates meaning you can get new functionality?

Does any website already have all these questions answered?

The site the actual physical Kindle uses depends on what country you've said you're in. If you go the Manage Your Kindle page you can change your country.

I'm not entirely sure what the full ramifications of switching your country around are. Obviously you'll get prices in Pounds or Dollars depending, and there's some sort of wierdness if you have a subscription to a magazine or newspaper when you change countries.

Since Kindle related to books, this country thingy can be funny. Just like someone mention magazine subscription is change from country to country, so is book sales. rules, regulations, market ownership, etc.

I live in Malaysia and I cannot even buy audiobook of Where The Wild Things Are.

IPhone and IPad have to be crack/unlocked (I didn't do this as I never buy any) because there is no real supplier (which is funny, there is a lot of apple reseller, but they are computer & software related, not telco, and they also have this problem with which telco should do what, should it locked to one telco - like US, or any telco?)

In other word, buy it if it sold in your country, or your country available as an option. If not, there is going to be a lot of things to go through.

On the topic, I went to Kindle page to see the news, and found out that neither Kindle or it's content are sold to Malaysia (wait, they didn't learn the story of mp3's and itunes , and iphone and ipads?).

Oh well.

But it wasn't truly their fault, it's how book market are planned in the old days and still in effect now.