The 1.4.1 version of VNCtalk for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac application is a product of VNC - Virtual Network Consult AG. The program lies within Communication Tools, more precisely Texting & Video calls. We recommend checking the downloaded files with any free antivirus.
From the developer:
VNCtalk is a native desktop application integrated with MacOS for professional and secure unified communication, with a full feature set of a comprehensive application for presence, chat, video/audio calls and web conferencing. The tool is designed for secure and private communication.
You may want to check out more software for Mac, such as Amigo, MySpaceIM or slitechat, which might be similar to VNCtalk.