One of my favorite sites for researching law on the Internet is American Law Sources Online (ALSO).
ALSO has compiled an outstanding, well organized collection of links to freely available primary and some secondary legal resources for federal and state law. It includes case law, statutes, local ordinances, administrative code, forms, research guides, and more. See the Wisconsin Sources page.
Links to some Mexican and Canadian sources are available, as well. There are also links to Uniform State Laws, Amicus Curiae briefs, law reviews and more.