If you’ve used any version of Windows, right from the beginning, i.e from Windows 95 to Windows 98 or Windows 2000 to Windows XP, you’ll find this feature called Microsoft NetMeeting.
It’s a built-in too for multi-point communication with others who are running on similar OS’es, ie, in simple terms it is software which uses the Voice Over Internet Protocol and lets you communicate, talk, conference and even video conference over Internet, with the only requirement being an active internet connection.
Download link for Microsoft NetMeeting.
Alternative Software for Microsoft NetNeeting: