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.
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."