Post date: Mar 07, 2012 7:34:30 AM
OpenCV's Haar training tutorial is here: http://opencv.itseez.com/trunk/doc/user_guide/ug_traincascade.html
short answer is
build and compile opencv
run opencv_createsamples to generate a .vec file which is a single file with multiple images in it all re-sized to the same size.
run opencv_taincascade on positive and negative images