If you have checked out a DEVELOPER'S COPY of Open MPI (i.e., you
checked out from subversion), you must first run:

shell$ ./autogen.sh 

You will need very recent versions of GNU Autoconf, Automake, and
Libtool.  If autogen.sh fails, read the HACKING file.

Everyone must run "configure" and "make" to build Open MPI.  Execute
the following commands to install the Open MPI system from within
the directory at the top of the tree:

shell$ ./configure --prefix=/where/to/install
shell$ make all install

To compile an MPI program:

C programs:   mpicc your-code.c
C++ programs: mpiCC your-code.cc    or
              mpic++ your-code.cc   (for case-insensitive filesystems)
F77 programs: mpif77 your-code.f

We do not yet have a proper mpirun program.  There is a script in
src/mpirun/mpirun that uses ssh to start individual MPI processes
(along with a bunch of associated environment variables); it will
eventually be replaced with a real mpirun command.