PDRhealth—The Physicians' Desktop Reference contains a wealth of medical information. But it's best known as a resource for detailed information on prescription drugs. This site catalogs any drug your doctor is likely to prescribe.
You can learn about the proper dosage for each drug. You'll see what you should avoid while on the drug. You can read about possible side effects. And you'll find advice on what to discuss with your doctor.
ClinicalTrials.gov—The medical field is always getting better. New drugs, technology and procedures are being invented. But each has to be tested before becoming available to the public. This testing happens in carefully monitored clinical trials.
This site catalogs the progress of more than 80,000 such trials. You can learn what research is being done. And you can see which trials are looking for participants. At the least, you may find things to discuss with your doctors.
World Community Grid—Your computer can connect you to many health resources. But it can also be a resource for others. Distributed computing programs allow researchers to use your computer. You can help them make amazing breakthroughs.