I'm sure someone else can you fill in on Chicago, but the only liberal paper I know downstate is "Illinois Times" which is a weekly paper that comes from Springfield.
Here's a link:
http://www.illinoistimes.com/gbase/Gyrosite/index.htmlI actually should start posting stories from them more often. They run Tom Tomorrow (which I'm not a big fan, but you can generally tell if a paper is liberal or not by the presence of that guy's cartoon), they focus on cultural events in Central Illinois, and they tend to have more liberal editorials. It's a start. If you are looking for Chicago, I can help a little, but like I said, I'll leave that to a larger expert.
On edit: I found this website for Illinois newspapers:
http://www.usnpl.com/ilnews.html It lists all the major newpapers in every town. You could hunt around and look at editoral pages, but I think for the most part it's all right wing or partisan outside of Chicago (which is funny because it's all right wing too at the Trib and Sun-Times). I try to read the Southeren Illinosan, State Journal- Register, Peoria Star Journal, Belleville News Democrat, and the Pantagraph. I would say the Pantagraph is the best of them all. Sadly, the Chicago Defender is not list on this site. Does anyone know if the Defender just doesn't have a website?