1. BizStats.com - Free statistics and financial ratios for businesses by industry; find out what the average firm in your industry spends and earns.
2. Business.gov - The central source for federal, state and local government information for businesses; learn about employment laws, where to apply for government grants and loans, and more.
3. BusinessFinance.com - This lender-matching service offers a range of useful information on various ways to finance a business.
4. Entrepreneurship.org - The Kauffman Foundation runs this site, which features hundreds of how-to articles for entrepreneurs, and data for policymakers.
5. Nielsen – Nielsen.com – Snapshots of consumer trends in different markets, from groceries to movies, by one of the oldest and biggest market-research firms
6. LadiesWhoLaunch.com – Blogs, success stories, how-tos and more, all targeting women entrepreneurs
7. Access eCommerce Guide – AccessEcom.info – Even internet-illiterate entrepreneurs can learn almost everything they need to start an e-commerce business here.
8. Small Business Advancement National Center - sbaer.uca.edu – The nation’s entrepreneurship researchers contribute to this trove of scholarly articles on small-business issues.
9. SmallBusinessSchool.org – View online videos and read transcripts of presentations on financing, hiring, exits and more.
10. Statistical Abstract of the U.S. – census.gov/compendia/statab – The U.S. Census Bureau’s comprehensive and authoritative rundown of statistics on America’s economy and society

Source: Entrepreneur Magazine April 2009