IBM Redbooks: Practical MPI Programming - Discussion of parallel architectures and writing MPI programs for distributed-memory systems. - http://publib-b.boulder.ibm.com/Redbooks.nsf/RedbookAbstracts/sg245380.html?Open
MPI: The Complete Reference - Online book describing the MPI standard and how to write programs with it. - http://www.netlib.org/utk/papers/mpi-book/mpi-book.html
Parallel Programming with MPI - Supplementary material, online drafts, and ordering information for a print book. - http://fawlty.cs.usfca.edu/mpi/