Harvard Law School Library. Annotated links to topics, guides and other good sites. Well organized by topics, including criminal law, human rights. Strong on U.K. sources. U.S. Dept. of State.
Index is good starting point.
Well-crafted site for many topics in public international law, including war and peace, nuclear, indigenous peoples, Middle East, international trade law, etc. . Major site for international commercial law, including important conventions, model rules and regulations , institutions, etc.