The International Criminal Court (ICC) and INTERPOL are independent organizations and not part of the United Nations. However, both the ICC and INTERPOL work closely with the UN.
The ICC also sits at the Hague and provides a legal venue for crimes of genocide, war crimes, crimes against humanity, and other international acts of aggression.
INTERPOL is headquartered in Lyon, France, and provides a way for national police agencies to cooperate in combating global criminal activity.
International law isn't confined to the United Nations -- if your research goes beyond the UN, you might find the following general law resources helpful:
The ICJ Yearbook (1946-2008, HeinOnline) has summaries of pleadings and cases decided by the Court.
Some ICJ judgements are also online in LexisNexis -- European Union, Commonwealth, and Foreign Nations content set. Select "International Legal Materials" from the list of sources.
Beyond the ICJ, the UN also discusses and attempt to codify international law. Several international tribunals have also been convened under the auspices of the UN.
Other organizations that have international judicial or "judicial-like" proceedings include:
In addition to UN documents that are binding on member states (e.g. Security Council resolutions), the UN also serves as a repository for bi-lateral or multi-lateral treaties.