Gaylen,

Have a look at Zetafax from Equisys, it's a very good product with lot's of features that you can use. It isn't the cheapest one around but we have been using it for years, DOS and Windows apps, and it never gave us any problems.
Sending a fax is as easy as putting a string like %%[Fax:xxxxxx] in the beginning of you're document and %%[Send] at the end. They have a API that you can use for all kinds of functions and even a new module to send SMS message's from any workstation.

Guillaume