Chris O'Donnell has a beautiful collection of free tutorials and videos on his site called creative Raw.
I highly recommend his series on "The Complete Guide to Luminosity Masks" for those interested in pursuing the technique. This is one of the very best places to start learning and using these tools.
His materials are excellent and free. You can view them on the web or download the videos and practice files.
He also explains how to get the Tony Kuyper's "TK6 Basic V6 Panel," how to install it and how to use it.