This little census tutorial highlighted a great tool - enter the address, then choose the level report you want - census tract, city, county, etc. You can map your choices, too. Especially helpful when working at the census tract level.
FASTEN Network
Neighborhood Data
Want to explore some more? You can also retrieve a lot of information about your city or even your neighborhood from the Census web page. To do this go to http://www.census.gov/main/www/cen2000.html and find the picture of the street sign followed by the words "Enter a street address to find Census 2000 data." (It's in the section between the red lines near the top of the page.) Click on the highlighted words "street address."