Shows making a simple concurrent program implementing a basic chat system; and how separating some processes and making them communicate is almost trivial in Erlang. ONLamp.com.
(ISBN: 0864447434) was written by Maurice Castro to support the course `CS584 Real Time and Concurrent Systems' at RMIT University in 1998. A revised edition is available in postscript form from this site in addition to the sample code used in the course.