Someone told me about a brand of yogurt that comes from France that was absolutely out of this world. She told me that she was able to find it at a kosher grocery store near where she lives (east coast). Unfortunately I didn't think to write down the name of the yogurt or the phone number of the person who told me about it. I am also going to post on the kosher message board in hopes someone can give me more information. I guess I could always check out some of the kosher stores in the Chicago area to see if they have it. If you have any information I would be extremely grateful. Happy eating!
you might also want to try specialty places like Treasure Island and Whole Foods and such. I normally get Stonyfield Farms yogurt, which is kosher.
Many many food products today are koshered because the only extra thing they have to do is have it inspected, and it expands the market. Kosher is one of the fastest growing categories of food produced today (a lot of this is due to the expanding Muslim population who follow similar rules - although Halal for meat is different than Kosher for meat). Many of the rules are about cleanliness, and US and IL rules are much stricter.
Note that Kosher does not mean vegetarian - as I understand it Kosher allows rennet from cows to be used in cheese. (I may be wrong, so don't quote me on this :)