vFax - Get a virtual fax number for as low as $2.99 per month and 3.0 cents per minute
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.
GotFreeFax - Send Free Fax Online to the U.S. and Canada.
Hellofax - Easy. Reliable. Online faxing. Send & receive faxes from anywhere.
Fax Pro - Simple, yet delightful way to send & receive faxes on the go.
ActFax - ActFax by ActFax Communication-Software GmbH - Fax Server and Email Software for Windows, Terminal Server, Citrix and Unix - ActiveFax Server