Nearly all private international law problems will involve researching the specific laws of both the U.S. (assuming a U.S. citizen or company is part of the legal scenario at hand) and one or more foreign countries. This is because, as stated before, there is not one well-defined body of private international law; rather, each country has its own way of handling private international law/conflict of laws issues. You will want to find out a country's rules about jurisdiction, choice of law, and/or enforcement of judgments depending on the facts of the case.
One useful starting point is Reynolds & Flores Foreign Law Guide:
For more information see the UCLA Law Library's guide to foreign law research:
International Aspects of U.S. Litigation by 
Foreign Court Judgments and the United States Legal System by 
Recognition and Enforcement of Foreign Judgments in China by 
International Commercial Arbitration and the Brussels I Regulation by 
Cheshire, North and Fawcett: Private International Law by 
Private International Law in the English Courts by  |  |  |  |
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