This is another good one I use. http://www.traillink.com/
The League of Michigan Bicyclists site ( http://www.lmb.org/ ) is a great resource where you can buy or download some really good bike tour and bike route maps. It includes their touring routes, like the Lake Michigan Coastline and Shoreline West tours, as well as MUPs, club maps, and MDOT maps.Here is a link to the online version:
www.trailsmichigan.com
I found some new rail trails around my area that I did'nt even know about. I plan on hitting a few next year.