Utilizing dual processors (Fortran)

I was hoping somebody in here had some experience in fortran.
I have a co worker who is running his fortran program on a single processor machine, but it takes about 10-12 hours to run a batch.
I am sitting with a couple of dual processor machines that does not have a very heavy load so we thought we could try to run them on my machines instead.
I though the smp kernel would automatically utilize the two processors, but apparently I had that wrong, because it sits and works with only one processor.
I can run a second batch at the same time and that will start up on the second processor, but ultimately, we want one batch to run on both processors.
I did some research (don't know much about this) and found a NAG library and OpenMP. Is this something I will need, or?
Is there a somewhat simple way to get this to work?

kernel 2.4.9-13smp RedHat 7.2.

Thanks./Fredrik