Hmmm... I think you're asking about practicing, not just reading fiction, right? I thought that Kim Harrison had links to Wiccan websites or books, but I've just visited her remodeled site and I don't see them anymore. I might be thinking of a different author, though. You know, many writers have blogs or forums that you can contact. I would contact one of them (say, Jim Butcher, Kim Harrison, Lori Handeland, or your favorite who writes about this stuff), and ask what books they uncovered as part of their research.
Good luck and happy hunting!