Identify your industry with North American Industry Classification System (NAICS)
Once you get a NAICS code use the Census Information to determine the number of businesses in your zip code
Look for industry/trade associations that will list companies in your industry
ABI/INFORM Annual Reports Annual reports browse by company name or industry
ReferenceUSA - Find a list of local competitors sort by Zip Code
Company profiles from Business Source Complete Find company SWOT and financial data here
Edgar - http://www.sec.gov/edgar/searchedgar/companysearch.html Search by company name or ticker symbol to find filings that will detail both strategy and financial data.
Market Share Reporter - Ref HF5410M35 2011 Well help you find the leaders in your industry
The company profiles link at the top of the page takes you to full text Data Monitor Reports
Enter the name of the company and press search.