Vault.com has a central location where engineers can go to find a great deal of information about their occupations. It is located at:
http://www.vault.com/hubs/eng_central_home.jsp?ch_id=609
On the left of the page you will see links to lists of employers broken down by specialty. Vault has done great deal work researching these companies. The information includes: Company Snapshot, Company Stats, and a message board. The message boards allow employees and ex employees to give information to the potential employee about the company. Take the information with a grain of salt if they are an ex-employee though.
