http://www.spiders.us/species/agelenopsi...
Very likely the Pennsylvania Grass Spider (Agelenopsis pennsylvanica)
There's 16 species within the genus. All look very similar outwardly. To confirm, is to establish range firstly, then examine the specimen under a microscope, looking at genitalia. Below is A.pennsylvanica & web (tunnel) from the Illinois State museum.
http://www.museum.state.il.us/ismdepts/z...
Dotted Wolf Spider
To complement Bills excellent response, these spiders are very harmless and eat a lot of pest insects.
Here is a different genus where I live, and I was able to coax the spider from her hide for the photo:
I live in Northwest Illinois. I found 5 of these spiders outside 2 windows of my house. They made a dense web with a funnel in the middle. The spider was waiting still in the entrance of the funnel. When I tried to touch it with a stick it hid away.
