In January 2008, I took Lori Nova's Cold Process Soap Making 201 Swirling and Layers class. As of today, I have not actually made a batch but I really like the technique as well as the class. But if you are not fortunate enough to live in the San Francisco Bay Area to take her class, I found a link that is the next best thing.
I know that this is not like being in a class, but it is the closet thing to it. If you have tried this recipe, let us know what you thought of it.
If you are interested in this technique for Hot Process, here is instructions on how to do it in the oven. I am looking for this technique for the crockpot. If I find the recipe, I will let you know.