The official answer is that you can't. PSN is not available in all countries, and PSN rules do not allow you to register an account in a country in which you are not a legal resident. People do it anyway, and there is nothing to stop you from doing so directly; but you won't be able to use a credit card to buy things in the Playstation Store if your PSN home address doesn't match the credit card billing address. You would have to use Playstation Network gift cards, in the currency of the country that you registered in. Those probably aren't available where you live either, unless you order them online. Most Caribbean countries are territories, or former colonies, of a country where PSN is available. If you are determined to use PSN, your best bet is probably to create an account for that country.