The new video calling feature has been made possible, thanks to the partnership between FB and Skype. Of course, you don't need to install Skype; a small plug-in takes care of the software requirements. On the hardware front, you need a webcam, a headset \ speakers, and a microphone.
Let's start with the basics, beginning with opening www.facebook.com/videocalling. The main page has a video on the right, explaining the feature. The Skype logo at the bottom of the screen reinforces the fact that it is powered by theVoIP provider.
FB Videocalling main page
To get started, you can click on the green Get Started button on the left of the screen. Assuming that you have already logged into Facebook, a chat window will pop up on the right hand side, listing all your online FB contacts. Click on one of them to proceed
Alternatively, you can start the chat directly from your online friend's profile by clicking on the Call button located on the right hand side of the screen near the top.
Calls can be initiated directly from your friend's profile
Once the chat window is open, you can click on the camera icon present on the title bar towards the left to initiate a video call