I already googled about screencast software on ubuntu. I found about

http://askubuntu.com/questions/4428/how-to-create-a-screencast


however is there a software which also uses the laptop webcam at the same time as recording the screen? so that I can have a small video of myself talking on top of the screen video which is being captured?

You will see this in some video tutorials that the full screen is occupied by the screen capture and then there is a small video at the bottom of the screen of the presenter as well.

Is this possible?