Here are some links to various sources of yoga information:

Free Yoga Books
Integral Yoga of New York
Sachidananda Ashram-Yogaville Virginia
IYI of New Jersey
Shree Maa & Swami Satyananda

Other Yoga Centers in the Princeton Area:

The Yoga Studio at Pennington
Princeton Center for Yoga & Health
Simply Yoga
The Freehold Yoga Center
The Yoga Meditation Institute
The Soma Center
The Saraswati River Yoga School & Center
Inner Light Yoga
Yoga Life Society