I live in Israel and I managed to buy a Kindle from Amazon. The non-US issued credit card is not a problem if you can buy anything else with it on the site (such as books). I used the services of a company called UsOneStop
- they provide a US address and then send you your package via DHL. In my case, the Kindle package was 3KG "dimension weight", so it ended up costing me $53 USD for the delivery.
I just checked - the shipping rate to Brazil on that site is insane! Almost $110 USD! Perhaps you can find a company that ships directly to Brazil...
But, 15 days after order and I'm a proud Kindle 2 owner, and I live nowhere near US