Qigong 氣功 is a term that represents a wide variety of practices. Most, however, rely on integrating body, breath and intention which is traditionally referred to as the "Three Regulations" - Tiao Shen 調身 (Regulating the Body), Tiao Xi 調息 (Regulating the Breath), and Tiao Xin 調心 (Regulating the Heart, i.e., mind).
The term Qigong is actually a modern one, stemming from the second half of the 20th century. It was coined to bring together a wide range of classical practices such as dao yin 導引 (literally pulling and stretching), nei dan 內丹 (inner alchemy), wai dan 外丹 (outer alchemy), zhan zhuang 站樁 (post standing), or chan si gong 纏絲功 (silk reeling).
Articles about Qigong
What is Qigong, An Introduction, by Henry McCann
The Man Who Invented Qigong - Liu Guizhen and the development of "Qigong"
Websites about Qigong and Schools of Qigong
World Taiji - the Qigong of Master Wang Feng Ming
Wushu Kung-fu Fitness Center - School of Chinese martial arts with extensive classical Qigong classes (East Hanover, NJ)
Ma Jou Miu Temple of New York - Daoist temple in New York, offering instruction in traditional Daoist arts including martial arts and esoteric Qigong
Pangu Shengong - the Qigong of Master Ou We Wei
Center for Tuina and Qigong Therapy of Pedro Yee
Yogic Engineering - information about a variety of yogic and Qigong related practices
Brochures and Booklets about Qigong
Videos about Qigong
Discovering Qigong (from the National Qigong Association) - An introduction to Qigong (introduction only)