The Census Bureau finished releasing population data from the 2010 Census. They created the useful interactive map below.
The data gets even more interesting at the state level. In Illinois, you can see the big growth in suburban collar counties - a trend mirrored across the country. What's missing at the county level is that Cook County, while experiencing a loss of population, had a big increase in the area surrounding the Loop. I'm guessing the .6% decrease in the black population statewide is largely due to the dramatic decanting of traditional black neighborhoods on the South Side.
This phenomenon, which again isn't unique to Chicago, is addressed in further detail here.