The SL version is in process. However, the most common problems that arise are not that dissimilar between Leopard and Snow Leopard. I often use the Leopard book to help with many SL problems. On occasion there are areas that are now quite different, but if you know the problem in Leopard then you can often figure out what's different in SL.
I've used the Xlab's troubleshooting guides since I purchased the first one for Panther. They are excellent but highly technical. Nevertheless, if you buy something like the MacWorld SuperGuide, I would also have the XLab's books. There's no such thing as one book that covers everything. The term "SuperGuide" is mostly a hype word to sell the book. Personally, I would prefer going to a bookstore so I could look through the alternatives before buying. Titles can be very misleading.
That said, one book well worth having is The Mac Bible. An enormous compendium but still one of the best of the breed.
Thanks Kappy. The Bible books.... well, I never open them. I have become allergic to books unless they are simple and save me a lot of time. I don't seem to have the technical ambition I once had.
The Xlab book sounds good but I think I will wait until SL version comes out since $ is an issue with me.
I've always liked Robin Williams Mac OS X books. Her books have always had both attention to the elementary user, and she doesn't put down the geeks either. And no this is not by the actor from "Mork and Mindy"
I happen to have Robin Williams "The Mac is Not a Typewriter" book and loved it. I like reference that is fast and simple since I am usually in a hurry to keep my projects flowing. Thanks!