The best way to get information about housing options is to contact the Admission Specialist in charge of your application. You should also have received information about housing options for graduate students with your admission packet.
There are dormitories with single and double rooms as well as apartments on campus for graduate students. There are two dormitories, McCormick Village and State Street Village. The latter is somewhat more expensive but newer. The apartments are the most expensive.
In addition to on-campus housing, you can also find apartments to share in the nearby neighborhood called Bridgeport. If you contact the Biology Department office ( http://www.iit.edu/csl/bio/people/administration.shtml
look for the department coordinator) you might be able to get information about off-campus housing options. Many students choose to live in the dormitories the first semester and then, when they know the city better, move off-campus.