Need a player to recored live audio and video

Sudheer writes: "Hi, I'm using GNOME on my Fedora Core 6 box. I'm looking for a software using which I can recored live audio and video on my desktop. The application must be able to record everything that is displayed on the screen. It would be great if the application can also record my voice along with the video. I would to use the mic for voice input. The purpose is to demonstrate how I use certain features of the applications installed on my computer. Once I record the video I will post it on my web site. Is there any Free and Open Source software that is capable of doing this?"