American Urological Association
1000 Corporate Boulevard
Linthicum, MD 21090
1-866-746-4282 (toll-free in US)
This site covers all conditions that affect the urinary tract. You can find a quick description of BPH as well as a link for further information. Also, there is a tool to help you find a urologist in your area.
National Kidney & Urologic Diseases Information Clearinghouse
3 Information Way
Bethesda, MD 20892-3580
Here you'll find a thorough discussion of BPH, including drawings and a glossary. You can also read up on the details of treatment, as well as the sexual changes that can occur and how to deal with them.