I realize this is old news to many, but it is still an amazing resource that should be mentioned here.
This website is easily the best resource for international information. I have used the CIA World Factbook to amaze my customers with my in-depth knowledge of the world. Using this site I talked one of my customers out of purchasing a titanium mine in Mali and helped another customer negotiate a better tax incentive with the government of Brazil.
If you have any international business, you need to bookmark: