As per help from Scott Teige the following command worked for me in installing openmpi with gortran with Max Os-x 10.5.
./configure --prefix=/usr/local --enable-mpi-f77 --enable-mpi-f90 F77=gfortran FC=gfortran --with-mpi-f90-size=medium --enable-mpirun- prefix-by-default
Thanks for the help. Frank
