Using a digital camera as a webcam?

Is it possible, if my digital camera has a video recording mode, to use it as a webcam? If so how?

I have a samsung digimax U-ca 505

Probably, most of the new cameras has that option, but they are not that good working as a cam, most of them shows the imagen too dark

I was told that a video camera does well as a web cam.I remember asking the salesman at Staples abt the choppy quality of the webcam and I think he said that the video cams are better and the picture quality wud be better!