Call conferencing, Paging and Windows 2008 support among major features added to software-based 3CX Phone System for Windows in record time
London, UK – 24 June 2008 - 3CX (www.3cx.com) has announced the release of version 6.0 of 3CX Phone System for Windows. The most recent version of the award-winning and software-based PBX ships with 10 [...]

Fonality has released the latest version of trixbox CE (Community Edition) today. This version has been a long time coming with major changes and new features included. Some of the new features include a more cohesive user interface, bulk extension importer, and expanded hardware support. For a more complete description of the changes, visit: http://trixbox.org/wiki/trixbox-ce-2-6-1.
Source: [...]

CallWeaver is a community-driven, vendor-independent, cross-platform, open source, PBX software project (formerly known as OpenPBX.org). It was originally derived from Asterisk. Now it supports analog and digital PSTN telephony, multi-protocol voice over IP telephony, fax, software-fax, T.38 fax over IP and many telephony applications such as IVR, conferencing and callcenter queue management.
Source: CallWeaver

FreeSWITCH is an open source telephony platform designed to facilitate the creation of voice and chat driven products scaling from a soft-phone up to a soft-switch.  It can be used as a simple switching engine, a PBX, a media gateway or a media server to host IVR applications using simple scripts or XML to control [...]

PHOENIX, Ariz. (AstriCon 2007) — September 27, 2007 — Digium®, Inc., the Asterisk® Company, today announced it has acquired Switchvox, a leading provider of IP PBX phone systems for small- and medium-sized businesses (SMBs). The acquisition bolsters Digium’s presence in the SMB market and provides a strong platform on which to advance its Asterisk-based unified [...]