Connecticut Technology Council - "A statewide association of technology oriented companies and institutions." Includes a searchable database of Connecticut technology companies. Search by name, industry, sales revenue, number of employees, city or keyword.

EDGAR - A database of corporate information, including SEC fillings.

Hoover's - Search for business information by company name, ticker, keyword, or executive name. Or browse by companies, industries, stock index, geography or the business boneyard. Basic information is free.