Business Source Complete (formerly Hoover's): our best all-around business database, it has a bit of everything, including journal articles, company profiles, industry overviews, country reports, and more.

Business Source Complete Advanced Searching video Tutorial (3:14)
 

NAICS codes
"The North American Industry Classification System (NAICS) is the standard used by Federal statistical agencies in classifying business establishments for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy."

IBISWorld: comprehensive industry reports and overviews, including:

• Investment Banking and Securities Dealing
• Commercial Banking in the US
• Securities Brokering

• Mergent Online  Current reports and historical data on US and international public companies. Profiles include a business summary, recent news, up to 15 years of financial data, institutional holdings, inside owners, subsidiaries, major competitors, and more.
• S&P NetAdvantage… info on stocks, bonds, mutual funds, industries.

Watch these short (& entertaining)  MarketPlace YouTube clips to review some basic terms and concepts:

Paddy Hirsch, senior editor @ MarketPlace explains....

• Crisis explainer
• Untangling credit default swaps
• Getting naked in short selling
• Uncle Ben goes shopping
• Repo 105
• Beware the carry trade!
• Margin calls and the financial markets decline
• Fannie, Freddie and the Fed
• Subprime
• Factoring
• Why investors are suing the banks
• Why 'Fallout' for the financial crisis?
• Shadow banking: still big, still dangerous
• Hostile takeovers
• Currency pegs
• How credit cards become asset-backed bonds
• PIIGS
• Counterparty risk
• Market makers, stub quotes and new SEC rules
• How the banks make the big bucks
• Ratings conflict
• Look out below!
• Bonds, notes and bills
• Wheres the toxic waste?
• Dark pools
• Quantitative Easing