Hi Teresa,
Has anyone on this thread already suggested the 'fileinput' module? From
what I understand, what 'fileinput' does is exactly what you're asking
from:
http://mail.python.org/pipermail/tutor/2007-April/053669.html
Here's documentation on 'fileinput':
http://www.python.org/doc/lib/module-fileinput.html
Good luck!