How-to-Geek: “…There’s no way to connect to a fax machine directly over the Internet, as the fax machine is only connected to telephone lines. To perform a fax online, we’ll need some sort of gateway that accepts documents via the Internet and transmits the document to a fax machine. That’s where the below services come in. Give them a document and they’ll do the annoying work of dialing up the fax machine and sending your document over the telephone line….”

See also via LLRX – Collaborative Law Firm: The Fax is Dead, Long Live the Fax