Prspct-l
You pronounce it "Prospect El." This is an online community for prospect researchers. For your free subscription, go to this web site. You can read and post messages on the web site, or via your email client.
Social Security Death Index
There are lots of sites where you can go to search this source. You would think that the results would be the same at each site, but you'd be wrong. Some sites, like Ancestry.com, charge to get results. Stephen Morse's site allows you to search several different sites: Searching the Social Security Death Index (SSDI) in One Step
Financial Dictionaries
SIC Codes
OSHA's server will give you an SIC code for your key words, or will give you a definition of a code you enter.
The North American Industry Clasification System was supposedly the successor to SIC, but both seem to be still currently in use. This is a list of codes and their translations.
IRS Wealth/Gift Statistics
What is the estimated percentage of of net worth represented by real estate? stock? cash? This IRS site will give you download-able reports on personal wealth that include a break down the assets of the nation's top wealth holders by type. Most recent data is for 2007. Scroll down to the section titled “ OI (Statistics Of Income) Bulletin Articles”, or go directly to the report here.
The poorest and wealthiest places in the US
Mongabay, which runs a nature oriented blog, has collected statistics on wealthy zip codes and demography.