So, there's this thing called the Hague Convention:
http://adoption.state.gov/hague/overview.html And these are the countries that are part of it:
http://adoption.state.gov/hague/overview/countries.html If you adopt a child from a Hague country, the adoption must follow the rules of the Hague convention. The convention establishes things like...children should be adopted in their home country first, and only placed internationally if they can't be adopted domestically. And that adoptions have to be handled on both ends by accredited agencies. These are rules designed to cut down on child trafficking, adoption of not-really-legally-orphans, and giving US adopters preferential treatment over in-country adopters. It's not perfect...China is a Hague country and has problems with all of those things. But it's a step in the right direction.
Haiti is not a Hague country, and the earthquake swept away most of their own internal systems for clearing orphans for international adoption. The initial group of orphans who were allowed to enter the US without paperwork were children whose legal orphan status* had been established before the earthquake, who had paperwork in process in the now-destroyed Port Au Prince Hall of Justice, and who had already been matched with US parents.
This thing where a bunch of people grabbed a bunch of kids to take them, supposedly, to a safe haven in the Dominican Republic is not part of any proper adoption proceeding, and is interfering with Haiti's sovereignty as well as interfering with the personal rights of those children and their families. Anyway, good rules of thumb for ethical adoption: 1. adopt from a Hague country, if possible, rather than a non-Hague country 2. whether Hague or non-Hague, scrutinize how well the law is being followed and what circumstances are used to justify exceptions. 3. don't adopt "disaster orphans" because it's very difficult to establish that they are really orphans, legally or actually.* 4. ignore the intentions of people in the process and focus instead on their compliance with the law and with accepted adoption ethics.
I'm generally a fan of international adoption even though I ended up adopting domestically (I'm also a fan of domestic adoption)--I think unethical adoptions happen all over the world, in huge numbers, both internationally and domestically, and therefore engaging as ethically as possible with whatever process you choose is the key thing, rather than only doing one sort of adoption.
*generally, a child who does not have a relative willing to claim them is a legal orphan, even if their biological parents are alive. Children relinquished to orphanages by living parents are sometimes legal orphans and sometimes not--in developing nations, parents may relinquish children temporarily to keep them alive, and retrieve them once they are able to feed them.