Many utilities have developed wind projects in the Midwest. This list is by no means exhaustive and should not be seen as an endorsement of any particular utility:
Minnesota Environmental Quality Board: Information on current wind power projects proposed for a site permit and projects recently permitted in Minnesota. In the search form select "Wind power" as subject and "Permit document" as Document type.
U.S. Dept. of Energy Green Power Markets: Green pricing information with a list of utilities that offer programs.
AWEA's Project Page: Lists of wind projects throughout the US, organized by state, and including Power Purchaser data