His claim to fame is alternative medicine, and Andrew Weil's Q & A Archive is a good example of the very clear patient information he provides on a variety of topics on his website. The site is heavy on the advertising, but I find his views refershing.
The Library of the National Medical Sociey is an interesting website. Lots of clinically useful stuff here. It's organized by the folks who publish the Current Clinical Strategies books .. those pocket-sized books with suggested admission orders for many common problems, etc. It's a subscription site, but the annual fee ($9.95) is nominal. I'm not sure that I would agree that the "journals" are in fact journals. While there is no advertising, there is also no mention of peer review, and the "articles" appear many times. For example, the same Sinusitis article appears in the "Journal of Medicine" and the "Journal of Pediatrics" and the "Journal of Family Medicine." Still, there are many well written, concise summaries to common clinical problems. The "online diagnosis" is a fun decision tool. While it doesn't rival Dxplain or QMR, it is a demonstration of both the complexity and potential utility of decision support.
The folks at LSU Deparment of Family Medicine and Comprehensive Care have published the Outpatient Management Manual from their Comprehensive Care Clinic on the web. It's a great resource for primary care educators. I found it on David Theige's site: Med-Ed News.
The National guideline clearinghouse is a good place to start if you are looking for a good guideline like this one. But (a common theme with government websites?) the layout of the documents leaves a lot to be desired. I prefer the layout of the same guideline at another good resource for guidelines, ICSI's website.