Law PORT is a collection of free-to-use training resources, created by library staff at the Institute of Advanced Legal Studies.
Recently added is an online tutorial on Judicial decisions in international law. This aims to provide an introduction to the background of the international courts (e.g. ICJ, ICC, ECHR) and the subsidiary role of judicial decisions in international law, as well as giving pointers on where to find decisions from a number of courts and how to access cases which are still in progress.
Worth a look if you're new to this area of law, or would like a refresher on where to find relevant case law.