http://www.betterbones.com/

betterbones.com
"Rethinking the true nature of bone health"

http://www.osteo.org/

National Institutes of Health
Osteoporosis and Related Bone Diseases—National Resource Center

see especially http://www.osteo.org/osteo.html
for NIH Facts and Figures, Risk Factors, and Prevention of Osteoporosis.

http://www.nof.org/

"The National Osteoporosis Foundation (NOF)
A resource for people seeking up-to-date, medically sound information on the causes, prevention, detection and treatment of osteoporosis."