General

BEOnline Plus  (Library of Congress)
 - select online business resources in 88 categories:
    accounting, business plans, e-commerce, demographics, data sets, directories, standards, etc.

BusinessUSA.gov  (Small Business Administration)
-  partnering with 21 federal agencies
 - compliance documents and resources
   see section for starting, managing, contracting and workplace safety or information on specific industries

Specific

Securities & Exchange Commission  - information about companies  - includes EDGAR Database
Fed in Print (Federal Reserve Bank) - gateway to FRB publications  Federal reserve Banks map  - many links to publications
Small Business Administration - starting and financing a business, opportunities, etc.
Treasury Department - accounting, budget, markets, international, etc.
Banking - FDIC information and reports, historical statistics, and more

Bureau of Economic Analysis - national, regional, indurstry and intermational stats

Economic Indicators, April 1995 forward, this monthly publication is prepared by the Council of Economic Advisers for the Joint Economic Committee. It provides economic information on gross domestic product, income, employment, production, business activity, prices, money, credit, security markets, Federal finance, and international statistics.

Economics and Statistics Administration - various commonly used economic indicators

County Business Patterns for the U.S. and every State; search by state, zip code or metro areas.

Statistics for Specific Industries - SBA, 7 major industries

U.S. Import/Export Price Indexes 1989- to launch database and Import/Export Price Indexes

Employment Statistics - Bureau of Labor Statistics

Federal Reserve Bank's FRASER (Economic Research) and FRED (economic time-series database)

U.S. Overseas Loans and Grants - Green Book, U.S. economic and military assistance to other countries: data given in historical (current) and constant dollars. Search by country or program; 1946 to present.

Macroeconomic Time Series Data Source Locator - international historical macroeconomic statistics 

Office of Women's Business Ownership - assists women in starting and running successful businesses.

Women-Owned Business Economic
Research,1995-
Compilation of studies, covering topics such as:
  - business ownership rates,
  - women-owned sole proprietorships,
  - venture capital in women-led firms,

Doing Business - World Bank resource for comparing business regulations, data and reports