Here's two online tools I recently heard about, that provide information on people or places.
Information on Places:
Zipskinny: Type in a zip code, and the website gives all kinds of demographic information (based on the 2000 census data). Also, you can type in up to 20 zip codes to compare locations in various categories (similar to one of my favorite city comparison websites, Sperling's Best Places), or see the top 100 zip codes for different categories (oldest, youngest, highest income, etc).
And who said public documents couldn't be fun?