The Cornell University Program on Applied Demographics (PAD) website possesses some great Census related resources. The first is a margin of error calculator for American Community Survey data which was created based on this U.S. Census Bureau document. The calculator allows you to enter values and operations in order to compute new margins of errors or test for significance of the difference between values.
Second, if you are looking for maps of current demographic data for the state of New York, then this site’s Census 2010 Atlas will be especially helpful. It has an easy to use index that allows users to choose what map to display. Once the map is displayed you can easily download a professionally prepared map in the form of a JPEG file.