Electronic Commerce Guide: Free articles and resources of interest to electronic commerce developers, web marketers, and business managers.
Fast Company: Magazine dedicated to reporting about how the "fast companies" (entrepreneurs, and cutting-edge) are doing what they do. Contains best practices, lessons learned, and cases.
Fortune Small Business: Fortune magazine's small business website. Updated daily with stories on e-commerce, finance, and marketing.
Line56.com: Features business-to-business e-commerce news, analysis and profiles of major players.