The Open Source Township GIS Project explores the use of open source tools to enable resource-strapped rural townships and NGOs (non-government organizations) in northwestern lower Michigan to produce geographic information science (GIS) data products and web applications easily and inexpensively.
For our purposes there are interesting sections on:
Note that there is a particular technical issue with Michigan Open map data (relating to "map projections of the class Hotine Oblique Mercator (aka Rectified Skew Orthomorphic [RSO] in other applications)".
The issue and workaround are discussed here.
There is also a very interesting tutorial on
Obtaining Color Aerials for your QGIS Project - about free colour aerial imagery from the National Agricultural Imagery Program (NAIP) of the US Department of Agriculture (USDA).