As a small business owner, I do my own marketing. So when I came across this web site, I found it very helpful in determining if I am focusing my marketing efforts on the right group to people.
Check it out. ZIPskinny will give you demographics in your zip code. I learned unemployment in my area is lower than the national average (able to afford my services). The average household income is also lower than I thought, at least (looking for value in my services). They also list age, race and education indicators on this site. Very interesting stuff.