The United State Geological Survey has released 2011 editions of the new "US Topo", the new generation of digital topographic maps. In October 2009, the USGS began to load US Topo maps to the USGS Store distribution point where the maps are available for free download. We have been waiting for the approximately 1,500 Michigan sheets to be released which just happened recently.
Search or zoom to your place of interest. Place a red marker on a location of interest, then click on the red marker to see a list of available maps. In addition to the new 2011 maps, you will also see older topographic maps available for free electronic download.
Please note that the new US Topos, while similar, are not exactly like the old topos. See this graphic to compare them side by side. Line features do NOT include section lines, Public Land Survey System lines, railroads, public buildings, and other features.