The Amateur Winemakers of Ontario - A very good collection of technical articles and resources for the amateur winemaker. Will even benefit professionals.
Amateur Winemakers Resource - Contains winemaking recipes and links for the home winemaker. Also lists wine+related ICQs.
Smalloak.com - Updated twice a month with links to winemaking articles and news. Includes allot of links to technical information as well as a technical discussion forum.
TheWineFly - Technical enology information, database tools, job contacts, and links for professional winemakers.
V and E Other Wine and Grape Related Links - List of academic, scientific and general links, from the University of California at Davis Viticulture and Enology department.
Wines and Vines Magazine - Monthly winery, viticulture and wine business updates and articles. Has good technical and marketing content.