Policy Map, a recent addition to the Penn Library website, is a great resource to go to for up to date demographic data. Just tap in a city or zip code and you have access to thousands of indicators related to demographics, crime, money and income, real estate, education, energy, and health. In addition to zip code and city, you can search by census tract, state, county, school districts, and legislative or Congressional districts. Policy Map generates its data in the form of maps, data tables and reports which can be easily exported as jpegs or pdfs. The number of indicators is noteworthy. You can get demographic breakdowns for ethnicity, religion, voting, etc. from a lot of sources but Policy Map offers many additional profile handles as illustrated by a search I did comparing obesity figures in Philadelphia in 2008 versus 2006.
Click here to read this article by Sharon Black on the Annenberg Library blog on February 22, 2010.