There are many fine books available about practising yoga. It might be very confusing which one is best for your needs as you start out. I might suggest you rent a video/dvd from a library if possible to begin practising with some guidance. Books are a little challenging to learn yoga from as it is an experiential art and science and often requires the guidance of a qualified teacher or at minimum, a good video. There are many quality videos produced by Gaiam with qualified teachers such as Rodney Yee, Rod Stryker, Patricia Walden and others. I think you will find the actual guidance the best place to get started and then the books will serve as follow and for deepening your knowledge.
I can appreciate the myriad of opinions relating to diet and yoga. The most connected topic comes from the ancient wisdom of the sister science to yoga; that of Ayurveda. The specificity and accuracy is remarkable and very much a lifetime of healing, balance and positive results coming from the profound wisdom of Ayurveda. There are fine schools and books in New Mexico. The best authors are Dr. Vasant Lad, Dr. Robert Svoboda and David Frawlely. There are also some fine Ayurvedic Doctors who travel and do seminars plus see clients for a short but very accurate assessment of ones constitution and related ways to heal. They are at www.amritaveda.com
There are many DVD’s on the market these days ranging from Restorative to Power yoga, all of them offering a different message and focus. Rodney Yee has several that I know are good. Eoin Finn from Vancouver BC has two power yoga DVD’s on the market that I believe you can get online both of which are fun and invigorating.