This tutorial is based on an excellent book by William Gropp, Ewing Lusk, and Anthony Skjellum, ``Using MPI -- Portable Parallel Programming with the Message-Passing Interface''. The book was published by The MIT Press in 1994, ISBN 0-262-57104-8, and it costs $US24.95, if bought directly from the publisher, whom you can contact by electronic mail.
However, you should be able to go through the tutorial even if you don't have the book. The tutorial is self-contained and references are provided to the basic MPI definition document which you can obtain by ftp anonymous.