There are (or at least, were) five show caves open to the public in Wisconsin. There is also at least one state park that contains caves that you can visit. I have put together some basic pages for these caves. There is also a park with caves south of Lake Winnebago. I will post more information when I get it.

Wyalusing State Park: There are at least three small caves that you can visit in this park just south of Prairie du Chien.
Cave of the Mounds: Brigham Farm, Blue Mounds, Wisconsin. 1/4 mile off of U.S. 18.
Crystal Cave: Spring Valley, Wisconsin. 1 mile west of town on State Highway 29. Updated for 2004.
Eagle Cave: Blue River, Wisconsin. 2 miles off of State Highway 60.
Kickapoo Indian Caverns: 200 West Rhein Hollow, Wauzeka, Wisconsin. On State Highway 60, 10 miles east of Prarie du Chein.