American FactFinder: 2000 and 2010 data from the U.S. Census Bureau
To search American FactFinder, visit the site.
If you're researching a neighborhood, start by using the Community Facts box, which lets you search by town or zip code (among other options). The address search option on the right side of the page is also very helpful (see image below). When you're done, click the Go button.
Now you'll have a list of the basic reports available for your geographic selection. The navigation on the left is arranged by subject. You can use those to navigate to the type of data you need.
When you click into a subject area, you get basic data about the subject and links to related reports.
Click on a report to access it.