«An Open-Source SIP Soft Phone»
SourceForge Siphon Summary Page
Siphon development is hosted on SourceForge. There, you can find everything: information for the Siphon mailing list, CVS access, public forum, download section, etc.

Vovida.org is a site dedicated to open-source software used in datacom and telecom. VOCAL (i.e. the SIP module required by Siphon) can be found on this site.

Siphon SourceXchange Project
SourceXchange is a marketplace where sponsors can submit projects to a network of open-source software developers. Siphon is a project sponsored by Vovida.org. All the Siphon project management is centralized on this site.

Quicknet Technologies Inc.
Manufacturer of VoIP hardware. Latest drivers for Internet Phone/Line Jack cards can be found there.