As the judicial organ of the United Nations and the only international court with general jurisdiction throughout all countries of the world, the International Court of Justice (ICJ) is the most important international tribunal, although the volume of cases decided by the ICJ is not so great as one might expect given its age. Only about 130 contentious cases have been brought before the ICJ since its inception. The predecessor of the ICJ is the Permanent Court of International Justice.
Under Article 34 of the ICJ Statute, only states may be parties in cases before the ICJ. IGOs or individuals may not be parties in cases before the ICJ. The ICJ can hear contentious cases if all state parties have agreed to the Court's jurisdiction or if jurisdiction is granted by a treaty. This applies to disputes that arise under the treaty, which may specify that such disputes will be decided by the ICJ, or if all parties make a unilateral declaration accepting the ICJ's compulsory jurisdiction. In addition, unlike a U.S. court, the ICJ may issue advisory opinions upon request of the U.N. Security Council, the General Assembly, or specialized agencies authorized by the General Assembly.
Summaries and digests of the ICJ decisions are available in print in the Library and digitally in HeinOnline's United Nations Law Collection. Also available at UIC Law Library 10th Floor - KZ213.F6 & KZ213.S8. Both Lexis and Westlaw also provide full-text access to ICJ opinions from the court’s inception until the present. Of course, the court has its own website, which provides links to cases in chronological order, starting with the current and going back to 1947. The materials available on the ICJ website include court records such as written and oral proceedings (i.e., memorials, which are like briefs) and other documents filed in connection with the case. Both advisory and contentious cases are available on the ICJ website. For more information about the ICJ, see the International Court of Just Research Guide at Columbia Law School.
The decisions of the Permanent Court of International Justices (PCIJ) (1922-1946) are also available on this website and in print in the UIC Law Library 10th Floor - KZ208.P47 ser. A/B. PCIJ decisions are also available digitally in the HeinOnline Foreign & International Law Resources Database.
International Legal Materials (ILM), also discussed in the Treaties tab, contain selected cases from international tribunals. There has been great growth in the number of international courts and tribunals. The Project on International Courts and Tribunals (PICT) created the following chart in an attempt to organize and display all of the various international courts and tribunals, past and present. While PICT has since been discontinued, the chart can still be found via the author's link.
For further information regarding international courts, see iCourts at the Danish National Research Foundation's Centre of Excellence for International Courts and Pluricourts at the Centre for the Study of the Legitimate Roles of the Judiciary in the Global Order.