Sheldon was probably the most prolific and quoted authority in the world. In addition to writing web articles on almost every aspect of maintenance and component selection, he has worked directly with mechanical problems coming up on bikeforums.com. Unlike some TdF winners, Sheldon answered his email. He will be missed.
Sheldon's website. Couldn't say how long the site will be up, so if you're interested in his articles, you might look it over soon. Actually, I suppose Harris Cyclery in the Boston will continue to maintain it.