Gathering intelligence on private companies can be tricky, as they are not required to file their financial and disclosure statements with the Securities and Exchange Commission. The first resource I've listed offers an overview of the best places to look. Running a search on the company name in the local newspaper in the town where it's located is another good tactic. I've listed directories of local business journals and newspapers in the second section along with some other unusual places to gather information on these elusive players. At the end I've included information on Google's new foreign news alerts.

Private Companies and Becoming an Expert

http://www.businessjournalism.org/content/3222.cfm
This page provides an outline from a presentation that identified, described, and provided links to sources that offer information on privately held firms. "Though geared specifically to business writers and journalists, this very handy summary of the best sources to turn to for locating private firms would be valuable to any business researcher. Consider this site if you need a quick overview of where to locate information on privately-held companies" from Best of the Business Web

A Gateway to Local Newspapers
http://www.newspaperlinks.com/voyager.cfm

Local Business Journals from Across the Country
http://www.localbusiness.com/

Political campaign contributions - Who gave what to whom.
http://www.followthemoney.org/
http://www.tray.com/cgi-win/indexhtml.exe?MBF=NAME
for federal campaigns dating back to 1980.

Lobbying - Does the company have a lobbyist, and how much are they paying them?
http://www.opensecrets.org/lobbyists/index.asp
"There are good stories behind companies spending lots on federal lobbyists"

Patents and Trademarks
http://patents.uspto.gov/
type in a company's name and see what they're getting patents for

Equal Employment Opportunity Commission
http://www.eeoc.gov/
The EEOC investigates charges against businesses for unfair employment practices or discrimination. "Litigation" section has a link to a monthly report on all of the actions taken by the agency.
http://www.eeoc.gov/litigation/settlements/index.html

Consumer products
http://www.planetfeedback.com/consumer/
search for complaints or compliments about a product or company

Foreign Language News Alerts
There are now four new foreign language news alerts from Google. Now you can track the news in French, German, Italian and Spanish.
http://www.google.fr/newsalerts
http://www.google.de/newsalerts
http://www.google.it/newsalerts
http://www.google.es/newsalerts