SIP-based (Session Initiation Protocol) Mac communications provider Nikotel is moving to an open-source model for development of its IP-telephony applications for Macs.

The company signs up 500 new Mac users every day who want to be able to make cheap telephone calls across the world using Macs and the Internet.

Its Mac application is called Mac2Phone. The next version of this application, which will be released as open-source code, will integrate SIP-based video conferencing. The company is also preparing solutions for the Windows, Solaris and Linux platforms.

Nikotel's SIP proxy development will also move to open source, using Xserves and Linux.

SIP is a standard that supports voice communications over IP. It is emerging as the strongest contender in the industry, establishing support from blue-chip companies including, Reuters, Microsoft and a variety of telecoms providers.

Mac2Phone users can communicate between each other using their Macs (or other platforms) at no charge. The system also supports calls to land lines and mobile phones, though these are chargeable. Nikotel operates a competitive tariff for such calls.

Users can also receive calls from mobile, fixed analogue phone-lines, or SIP-based telephones. Users must be running OS X 10.2, and have a microphone and speaker installed.

The Mac2Phone software is freeware and is available directly from Nikotel's Web site.