Face Detection can be achieved quite easily by using
Emgu CV[
^], which is a C# wrapper for Open CV. All you have to do is to download the Emgu CV, then use the sample code provided for face detection using webcam from
http://www.emgu.com/wiki/index.php/Face_detection.
You will need to include Haarcascade file named
haarcascade_frontalface_alt2.xml
for face detection as well.