I can send a FAX by email using www.j2.com cost 5 cents per 30 seconds. Typically the body of the email Faxes ok but is
fine light print. You can leave the body blank and include
an attachment in the .tiff fax format. j2 provides a utility
that allows you to print a word document to a "fax printer"
which opens a blank email with the attachment. All you
have to do to send is fill in the TO field
with the number 12075551212@j2send.com. It works for
international faxes too (country code city number). So, you
could hack ns_sendmail to send your faxes and use an external
service. Using a built in FaxModem might be more complicated and
you still have to pay for LD services...
-Bob