I just started teaching my course on "Jewish Folk Religion: Magic and Ritual Power." When I was putting in a book order for the course, I included Joshua Trachtenberg's Jewish Magic and Superstition (1939) because it's a classic and much of it is still very useful. I found out from the bookstore that it's now available in its entirety from Google Books (for free) and that Sacred Texts.com has also just put it online - at http://www.sacred-texts.com/jud/jms/index.htm. I think the Sacred Texts version is easier to use. Both versions have all of the illustrations as well as the notes.
For those interested in seeing the course syllabus, I've posted it as a Page (see link on right side) , leaving out the sections that are only of interest to the students in the course (like the rules for how to behave in the classroom), but including everything else.
It was interesting putting together the syllabus. I first taught the course in 2004, but I wanted to include more anthropological theory (it's now cross-listed with the anthropology department), so the first three weeks are devoted to theory. At the end of the course I'm going to include more about contemporary Jewish magic, principally in Israel. I found a good article by Zion Zohar on the invention of the Pulsa DeNura curse and its use in Israeli politics - "Pulsa De-Nura: The Innovation of Modern Magic and Ritual" (Modern Judaism 27  72-99). I'd like to find more articles in English about other manifestations of Jewish rituals to gain power in contemporary Israel - especially about the use of amulets and the contemporary use of the ritual to exorcise a demon, and how it has become politicized.