The State of Michigan, through the Michigan Electronic Library, has wonderful digital resources to explore about local history and genealogy.
Local history resources [1]digital versions of Civil War Diaries, images of early Detroit, Michigan county histories, photos from Idlewild, and oral histories of Holocaust survivors are just a sample of resources you can find on this website.
Genealogy Gateway [2]has links to resources as varied as: books about Michigan cemetaries, the Bostonian Society, the Othodox Church in America, and Radio City Music Hall archives.
Links:
[1] http://mel.org/index.php?P=SPT--BrowseResourcesMichigana&ParentId=687
[2] http://mel.org/index.php?P=SPT--BrowseResourcesGenealogy&ParentId=839