SkypeJi is an open/free/libre PBX solution based on VoIP software Skype.

I guess PBX and Skype got your attention. Well, in its true sense it is not a PBX, as it does not support any telephony interfaces and protocols. It is primarily a tool to manage multiple Skype users through a common web interface, using Skype APIs, thus creating a PBX like solution.

Functional Objectives

- Administration
    o Manage User Accounts
    o Manage Contact List
    o Manage User Classes

- End User
    o Check User's availability Status
    o Make/Receive Calls
    o Leave/Check Voice Mail

It is based on open architecture, thus making it easy to integrate with any other applications like Intranet Portals, CRMs, Group Collaboration softwares etc.

Pre Alpha Release 0.2 is out
It includes:
New Documentation, XML support, and database schema

check for details