For information on anything and everything in the state, contact the Wisconsin Department of Tourism (800/432-8747, www.travelwisconsin.com [1]), which has a decent website and offers fantastic printed guides.
Regarding the Internet, precious few sites are really all that worthy. First stop for culture, arts, and history should be portalwisconsin.org, a superb site; cheekier but filled with tidbits is classicwisconsin.com, good for information on fish fries. An idiosyncratic site—is it travel or geography or what?—is www.wisconline.com [2]. You can thereafter peruse all you want, but this author has never found an otherwise worthy website on pan-Wisconsin travel.
Links:
[1] http://www.travelwisconsin.com
[2] http://www.wisconline.com