FSP is a process specification language based closely on CommunicatingSequentialProcesses.
http://www-dse.doc.ic.ac.uk/concurrency/
Minor differences from CSP are:
http://www.doc.ic.ac.uk/~jnm/LTSdocumention/FSP-notation.html
http://www.google.com/search?q=Finite+State+Processes+-FSM