Hoover’s Online
Search for business information by various categories like company name, stock quotes and news. You can also browse through companies (by alpha, geography, stock index), industries, etc. Some information is free but others are for subscribers (like Hoover’s In-Depth that includes company overviews, history, key people, products, competitors, etc.) It’s useful for general information—had fact sheets for each company that includes information about sales, net income, growth, employees, etc.
Fortune
Features categories: Companies, CEOs, Investing, Careers, Technology, Small Business, as well as news articles, current events, ratings (the famous Fortune 500 and 100 best companies to work for). However, you must be a subscriber to see much of the information.
US Census Bureau
Here you can find statistics about business size. Categories are defined in terms of Employers and non-employers, Size of firms, Size of establishments, Receipts size of firms, and Legal form of organization.
CorpTech
You must buy a package to access the information. The website has samples you can see before you buy. Information includes company information including sales leads, company research, mailing lists and competitor analysis. It claims that you can "get unlimited access to over 285,000 decision makers at more than 95,000 high-tech companies" by 32 different ways including industry, executives, geography and products.
Monster Company Boulevard
Choose a company by alphabet to view their company profile. The profiles are overviews that seem to have come from the companies’ websites.
Business.Gov
Find out about what Federal and local government laws and regulations are concerning launching, managing, and expanding businesses.
Small Business Administration
A resource for small business owners. Includes the Federal laws and regulations that govern small businesses.
Inc.Com Resource Center
Every year Inc.Com publishes a list of 500 of the nation’s fastest growing private companies.
Research Magazine
A print magazine that offers its issues free online. Research Magazine provides a resource on corporate profiles, news, and stock exchange information.
Business Wire
A large database of company press releases as well as selected corporate profiles. You must register at the site to see the full text of press releases and search for corporate profiles.