National Cancer Institute at the National Institutes of Health
National Cancer Institute: Prostate Cancer Home Page
This site by the National Cancer Institute provides a general overview of prostate cancer. Also provides links to more detailed information about stages, treatment, prevention, genetics, causes, and screening for prostate cancer.
Other
National Kidney Foundation: Prostate Cancer
This thorough site defines what the prostate is, explains the cause of prostate cancer, lists the symptoms of prostate cancer, and delves into tests and treatments.