Two business databases, ABI Inform Complete and Business Source Premier, are the best sources for locating articles a wide variety of articles on companies. LexisNexis is an excellent for locating articles in news sources both US and international.
Wall Street Journal (through Proquest/ABI)
Other useful resources include
Academic Search Complete (for interdisciplinary approaches)
Google Scholar (interdisciplinary and scholarly)
Link to All Library Databases
Use these sources for a quick overview of a company.