Wikipedia on Scuba Diving

Find out about breathing underwater, effects of breathing high pressure gas, avoiding losing body heat and other issues involved in scuba diving.

http://en.wikipedia.org/wiki/Scuba_diving

PADI

The Professional Association of Diving Instructors will show you how to start diving, advance you level and eventually teach the subject.

http://www.padi.com/padi/default.aspx

About Scuba

Information for beginners, certification process, careers, dive shop operators and more on this scuba portal.

http://scuba.about.com/