I’m sorry i dont have windows, nor do i have access to any windows machine right now so i cant provide you with a working example for it.
But you can get a simple, somewhat over-commented sample running fine on linux here:
http://home.arcor.de/positiveelectron/files/artoolkit-sample.zip
to make it work under windows see the code-comments. it should not be that hard. just a matter of changing the webcam input to WebcamVideo.
everything you need should be included. the patterns and camera-calibration files are taken from the original artoolkit-sources.