Firemaiden, I took two three-day seminars with Debbie and Sue about six years ago in southern Colorado. They were brought here by the owners of a new metaphysical shop and I found both ladies to be wise, witty and warm. And they REALLY know how to read playing cards!
The main feature of the Cards of Illumination method of reading playing cards is its tight relationship with astrology. The timing of events and life cycles is impeccably outlined. The system has almost nothing directly to do with tarot, but it does help one to read tarot cards better due to the traditional suit associations between tarot and playing cards. Debbie and Sue insisted that only a standard poker deck (no "designer decks") would work with the system, owing to its archetypal and historical roots.
Sue and Debbie learned from the developer of the system, Robert Camp. Robert has published several wonderful books about his method and these books are readily available through Amazon and at almost all of the larger bookstores like Waldenbooks, Borders, etc. He also produces software to go with the system!
At the time I took classes from Debbie and Sue, there were three seminars one could take: beginning, intermediate and advanced (with a Certified Card Science Reader "diploma" awarded at the end of the last class). Unfortunately, they were unable to return to my town for the third and final class, so I never got to take it. They may have changed the class format by now.
Sue and Debbie were thinking about writing a text when I met them, but as far as I know they haven't done so yet. If you are interested in learning more about this system, I urge you to read Robert's books because they are wonderful!