GotFreeFax - Send Free Fax Online to the U.S. and Canada.
ictfax - ICTFAX is web based and open source Fax software, It is multi users and suitable to offer online Fax services, including Email to Fax, Fax to Email and Web to Fax. ICTFAX application support FoIP, T38 and G.711 pass through faxing also PSTN fax.
Hellofax - Easy. Reliable. Online faxing. Send & receive faxes from anywhere.
HylaFAX+ - HylaFAX+ is an enterprise-class open-source system for sending and receiving facsimiles as well as...
faxZero - Internet fax application.
FaxTalk FaxCenter Pro - Easy to use Windows fax software, broadcast fax, network fax server, answering machine software for home and small business.