Web Camera

A simple Webcam setup consists of a digital camera attached to your computer, typically through the USB port. The camera part of the Webcam setup is just a digital camera there's really nothing special going on there. The "Webcam" nature of the camera comes with the software. Webcam software "grabs a frame" from the digital camera at a preset interval and transfers it to another location for viewing. If you're interested in using your Webcam for streaming video, you'll want a Webcam system with a high frame rate. Frame rate indicates the number of pictures the software can grab and transfer in one second. For streaming video, you need a minimum rate of at least 15 frames per second (fps), and 30 fps is ideal. To achieve high frame rates, you need a high-speed Internet connection.

Different Needs of Webcamera
In order to create a simple Webcam, you need three things:
A camera of some sort connected to your computer
A piece of software that can grab a frame from the camera periodically
A way to broadcast your images on the Web