Here is a map of all the bike trails in the Twin Cities. Minneapolis contains more bike trails than St. Paul and more beautiful city lakes. All the dark green are off street bike paths. Using Google maps, anyone can use the feature to examine the different bike trails in your location. Google obtained much of its data from the Rails-to-Trails Conservancy in putting together the maps, and has detailed information on bike routes in 150 U.S. cities
Bikers are be able to find bike-only paths, bike lanes on city streets, and bike-friendly streets when searching for directions using the tool. Google will also include an estimated travel time alongside the results that factor in hills and fatigue. There is also a Terrain Map that works in-conjucntion with the bicycling path map.
I ran into a website called Map My Ride today while browsing the web. MapmyRIDE started as a means to help cyclists chart and track the rides they completed along their travels.