Line56.com - Features business-to-business e-commerce news, analysis and profiles of major players. - http://www.line56.com/
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. - http://www.fastcompany.com/
Fortune Small Business - Fortune magazine's small business website. Updated daily with stories on e-commerce, finance, and marketing. - http://www.fortunesb.com/
Electronic Commerce Guide - Free articles and resources of interest to electronic commerce developers, web marketers, and business managers. - http://www.davidreilly.com/topics/electronic_commerce/