running a stand-alone executable from within a python program

[Aimee Taylor]

Is there a way to run stand-alone executables from python?  It would
be great if there was a way to do this independent of platform, but if
not, these are my needs:

Right now I have a stand-alone fortran 77 program that I want to run
from a python program on a PC.  I will also be putting all of this on
a mac someday soon (of course I will also be changing the fortran
program some and compiling it on the mac).

Future plans:  I'm not up to threading yet, but someday it would be
nice to execute the fortran program on a separate UNIX box(es,
parallel processing far in the future??) and pipe back the resulting
text file to the PC or MAC client.

Thank you for any ideas/suggestions in advance!  
--Aimee