These are links that I like:
 

Jarek Szymanski's pages   are full of good research into Xinyi, Xingyi, Bagua, 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.
 
http://www.theopenminddesignersima.com/" Open Mind Designers IMA - A source of study and research in the field of  Internal Marial Arts.