Lots of people misspell Stewart's name.
Oopsie
There are lots of great books available on doing spellwork. I just saw one by Judika Iles in the store the other day. It's called "Pure Magic: A Complete Course in Spellcasting" and if it's like her excellent "Encyclopedia of 5000 Spells" it should be good.
I also really liked Nancy B. Watson's "Practical Magic" as it's a solid nonsectarian introduction to magickal work.
I'll have to look those up. Great, my amazon wishlist shall grow yet more....