ExtraWebcam is the software that enables you to use Canon PowerShot and EOS series cameras as regular webcams for video conferencing, video recording, remote area monitoring and other webcam tasks.
It supports any Windows software that take a standard video capture source as input such as Skype, MSN, AIM, Yahoo Messenger as well as online services like Ustream, Veetle, YouTube. You only need to select ExtraWebcam video source, connect your camera via USB and power it on, the rest will be done automatically - search for a connected camera and taking control over it.

ExtraWebcam has a tray icon utility that helps you to work with your camera. You have the live viewfinder window there and camera settings controls like shooting mode, shutter, aperture, ISO, white balance, zoom. You can use ExtraWebcam for automatic interval time-lapse shooting, it's possible to record video stream and time-lapse sequences into MJPEG AVI files.

List of supported cameras:
Canon PowerShot A60/A70/A75/A80/A85/A95/A300/A310/A400/A510/A520/A620/A640
Canon PowerShot G2/G3/G5/G6/G7/G9/G10
Canon PowerShot Pro1
Canon PowerShot S1 IS/S2 IS/S3 IS/S5 IS
Canon PowerShot S30/S40/S45/S50/S60/S70/S80/S400/S410/S500
Canon PowerShot SD100/SD110
Canon PowerShot SX100 IS/SX110 IS
Canon IXY 200a/300a/320
Canon IXY PS S200/PS S330/PS S230
Canon IXY IXUS v2/IXUS 330/IXUS v3
Canon IXY DIGITAL 400/500
Canon DIGITAL IXUS 400/430/500/II/IIs
Canon EOS 1000D/450D/500D/550D/40D/50D/7D/5DM2/1DM4

Features
xtraWebcam starts automatically when a chat or other application starts using ExtraWebcam videosource, or you can start it standalone at any time clicking on it's desktop or menu icon. When it starts automatically it's main window doesn't show up so if you want to check settings or use viewfinder click on ExtraWebcam's tray icon to make the window visible.

Main window has CONNECT checkbox, when ExtraWebcam is being used by another application camera connects automatically, in this case CONNECT switches viewfinder video on and off, when running standalone CONNECT initiates camera connection/disconnection.

Videosource box has four items: "None" disables video output, "Live Viewfinder" selects 320x200x30fps streaming video, "Single Shot" makes output of manually taken still images up to 640x480 resolution, "Interval Shooting" mode automatically takes pictures with a configurable interval, the resolution is up to 640x480.
AF Lock checkbox locks current focus so interval shooting doesn't refocus before each frame, it takes less time of taking a shot and it's useful when you want to make a video from saved pictures and wish to keep same focus for all frames.
Refocus button forces camera to refocus in Live viewfinder mode.
Log tab contains a text log of connection/disconnection process, software update events.

Camera settings tab has various shooting parameters controls.

Compact view tab makes a smaller "always on top" window that has only camera shooting parameters, this mode is useful when you're in fullscreen mode and want to keep controls visible.

Options tab has controls for enabling/disabling of software update, connection/disconnection popups and optional saving of all pictures taken in single/interval shooting modes.