Hi K.,
I would also look at your surrounding park districts to see what they offer. Also, Music Together is great for music. You also might want to see what your local hospital offers as far as classes. I know that Edwards in Naperville and Good Sam's in Downers offer classes for moms and tots, but on a limited basis. Also, don't forget about your local library! They usually have a storytime and it is a good way to meet other moms with kids your child's age.
As far as preschools, you might want to check with your local PACES Group (http://www.pacesmoms.com/region_2.html). You can purchase a Preschool Guidebook ($5.00) and talk to them about attend a preschool forum.
Good Luck!
S.