http://www.uspto.gov/ip/global/enforcement/

"The Enforcement Team's mission is to improve intellectual property protection and enforcement domestically and abroad. Since the rights granted by a U.S. patent extend only throughout the territory of the United States and have no effect in a foreign country, an inventor who wishes patent protection in other countries must apply for a patent in each of the other countries or in regional patent offices. Almost every country has its own patent law, and a person desiring a patent in a particular country must make an application for patent in that country, in accordance with the requirements of that country"