How do you model concurrent systems?

In this semester, I am studying a course titled "Concurrent and Distributed Systems". The main objective of this course is to model concurrent applications. We are using a modelling notation called FSP for describing concurrent processes. This language is developed by Jeff Magee & Jeff Kramer and demonstrated in their book "Concurrency: State Models & Java Programs". Apart from the language, the interesting thing is the tool written by them to model/verify the whole process. This tool is called Labelled Transition State Analyser (LTSA) and is available from the author's website (http://www-dse.doc.ic.ac.uk/concurrency/) . I dont think that this modelling approach is widely adopted and neither it is easier to learn, but I wanted to ask your opinion about any other modelling tools available for concurrent and distributed systems.