Breathing

The Pranayama Institute
Information on techniques of Hatha and Raja Yoga Pranayama can be downloaded.
http://www.pranayama.org/

Rhythmic Breathing
Exposition of a natural, full twenty four hour rhythmic breathing practice. Includes diagrams, charts, a free newsletter, and a schedule of meetings.
http://www.3srb.org/

Vaasi Approach
Vaasi yoga is a technique of channeling the breath in sushumana nadi energy pathway. This site is dedicated to teaching that philosophy and practice.
http://www.geocities.com/HotSprings/Sauna/2188/index.html