pages are full of good research into Xinyi, Xingyi,
and Taiji. If you like my site, you love this one.
http://www.chiflow.com/ offers solid information on Nei Jia Kung Fu. More specifically Jiang Rong Qiao's Bagua, Xingyi, Taiji, as well as Wu Style Taijiquan and Ma Yueh Liang.