Hello, and welcome to the theremin. :)
Carolina Eyck's method book is highly recommended, even by me. It's a very well detailed book, complete with a photo chart of the finger positinos, and exorcises. Some of my students use the Eyck method.
Also, there are two free publications which are quite good indeed. Those are: Clara Rockmore's Method booklet which can be found in the Learn To Play section here at Thereminworld, and the other is Victor Estrada's Exorcises for Theremin. I believer there's also a link here at TW. Both are free downloadable PDFs. These also have charts and exorcises as well as having been well written. Estrada's book is also at his site at: http://www.victorestrada.com Be sure to click on english version.
There are also several DVDs from Peter Pringle, and my self, as well as the one that comes with the Moog Music Etherwave Standard, which features an lesson by Lydia Kavina.
I must point out that it's important to watch and listen to as many different thereminists as possible, and ask your self which of them sounds best, and seems to use a method that might suit you best. Keep in mind that you want a method that's not going to present RSI problems down the road, but offers the best quality of playing in the end.
I wish you all the best with the theremin. Don't hesitate to ask if you have further questions. One of us will be happy to help. :)
