For market research, as with business industry research, you go very quickly back to the Web. Here are some starting points:
marketresearch.com — MarketResearch.com is a commercial site aggregating published market research.
jjhill.org/ — Hill Research Library, an excellent nonprofit library resource, offers market research at accessible rates.
sba.gov — This is the U.S. government hub site for market research.
clickz.com/stats/ — ClickZ Network offers up-to-date statistics on Web usage.
census.gov — The U.S. government statistical site.
knowthis.com — KnowThis.com is a marketing information site.
marketingpower.com — American Marketing Association (AMA) main market information site.
hoovers.com — Hoovers is a database of American companies.
ceoexpreass.com — Offers a wealth of links for additional information sites.
bea.gov — The Bureau of Economic Analysis is part of the U.S. Department of Commerce, offering business statistics.