Illinois does not allow the sale of home-baked goods.
You may be able to build a second commercial kitchen in you home, but you need to contact the licensing entity to find out.
If you look in the cake decorating business forum, there is a post :
New: states that license ...... There is a link there for Illinois.
What part of IL are you in? I made a post quite a while ago which listed many of the requirements for IL for a licensed kitchen. I'll see if I can find it and post a link here for you.
Hmmm... it looks like the post may have been lost in the 'great crash'. Well, you need:
Scrubbable walls & ceiling
Light colored floors
3-Bin sink (or dishwasher), hand sink, mop sink
Most likely a greasetrap for the 3-Bin sink
That is just a few of the requirements. When you take a food sanitation course, many of the requirements will be discussed. Things like proper food storage at least 6" off the floor, etc. And, yes, all of those things are required even for a licensed kitchen in your home. Which can NOT be the kitchen you prepare food for your family in. It must have all separate appliances (no sharing w/your family kitchen) and be able to be closed off to family/pets w/a door. All electrical and plumbing work needs to be completed by a licensed electrician/plumber. You will need building permits and final inspections by the building department, electric, plumbing, fire & health departments. And of course, they all have their fees to do this. Know what all of these costs are up front- they can sneak up on you! All of this is quite doable, don't get too discouraged. Just knowing what to expect is a great start. 
Here is a link to a post that I did find, but it's not the one I originally went looking for.
http://forum.cakecentral.com/cake-decorating-ftopict-313783.html
Good Luck with your endeavor!!!
Hi, I am in northern Il. Machesney Park , Il Wow that sure makes it out of my reach to do this in my home. I didn't think you had so many restrictions. My daughter and I were going to do this at home . I guess that will be out of the question for now. Thank you though for all of the information. I still like to bake so I guess I will continue to bake for just my family.
Kirin1 
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